The Delhi Conspiracy Commission was created on 9 April 1930 by an order of the Chief Commissioner of Delhi, exercising his special powers under section 3(1) of the Code of Criminal Procedure. The commission was directed that certain persons shall be tried by it for the offence of conspiring to wage a war against the British King. The number of accused to be tried by the commission was 24 in all. Out of these 24 persons, 14 were arrested and produced before the commission, while nine were declared absconding, and one had died. Though only 24 persons were accused of the offence, during the trial it transpired that there were a large number of persons who had participated in the venture. It was an Indian revolutionary movement directed against the British to win India's freedom by violent revolutionary means.

Constitution of the Commission

The three-member commission consisted of L.S.White (president) and members Kanwar Sain and Amir Ali. During the trial of the accused persons, the Crown was represented by Muhammad Zafarullah Khan and his team. The accused were represented by Asaf Ali with support from others.

Accused before the Commission On 14 May 1931, nine accused were presented before the commission. These were Nand Kishore Nigam, B.R. Gupta, Rudra Dutt Mishra, Bhagirath Lal, Hardwari Lal Gupta, K. R. Gupta, Harkesh Singh, Gajanand Potdar and Kapur Chand.

On that day, the Crown presented Kailashpati, who had turned state's evidence, as a witness. Asaf Ali, who represented the accused, attempted an objection to the oath being administered to Kailashpati on various legal technicalities. The Commission overruled the objection and directed the administration of oath. The memory of Kailashpati was phenomenal and he gave such a vast volume of detailed information on every minor and major subject, which ran into about 900 pages of deposition, that it became impossible for the prosecution to tie the loose ends of the story to secure conviction for the accused. It was primarily for this reason that at the final stage of the trial, the commission was disbanded by the Government before a verdict could be given by it.

The prosecution also presented other approvers in support of its case. These included Girwar Singh, who was produced on 24 February 1932 by the prosecution, and Dandpani Venkat Tailang, who was examined by the prosecution on 8 March 1932. Other approvers included Ram Lal, Madan Gopal and Bal Kishon (alias Kishen Bal).

Barhelganj post office robbery The primary goal of the Hindustan Socialist Republican Association (HSRA) was to gain independence of India from Britain by use of armed revolution. Kailashpati had been introduced to the movement in 1923 and in March 1928 he was asked to assist it by robbing his employer, the post office at Gorakhpur. He was transferred to the branch at Barhelganj before finding a suitable opportunity to carry out the scheme. On 26 June 1928, he took all the available funds held by the Barhelganj office, being around Rs. 3000 – and travelled with it by train to Cawnpore. He gave some of the money to Haldhar Bajpai and the remainder to Surendranath Pandey, with whom he stopped for two days. He then briefly moved into the room of Sheo Verma at the DAV College Hostel, where he met Sukhdev Raj, who was known as "Villager", Chandrashekhar Azad and Gaya Prasad. The group then split up, with Kailashpati moving to Lahore.

In needs of funds in late 1929, the group determined to rob the Punjab National Bank in Lahore but the plan was first postponed and then abandoned

"The Himalayan Toilets" Armed revolution required weapons, and at that time the HSRA had only small arms such as pistols and revolvers. Aware of the shortage of firepower, the HSRA sought to improve its position. They took to learning about chemical reactions from books in order that they could make bombs, then experimented accordingly. The successes were stockpiled and used in their missions, albeit not with great success. Sachchidananda Vatsyayan was known within the group as "Scientist" and was involved in the bomb-making activities. Babu Ram Gupta was a revolutionary and he used his shop in Billimaran as a facade for the purpose of buying bomb-making materials on a regular basis.

The intent was to manufacture picric acid, for which carbolic acid was also necessary. Towards this end, various items were bought through Gupta, including some sulphuric and nitric acids that were stored at Kailashpati's house until around the end of July and the beginning of August. At this time they were taken to the bomb factory, which was known as "The Himalayan Toilets" and bore signage accordingly. For these materials, which also included sundries such as rubber gloves and some potassium cyanide, Gupta was paid Rs. 600. Two electric fans were also required and were hired by Bimal Prashad Jain. The fans were used to expel the fumes from the factory and, since picric acid turns water yellow, any water expelled from the factory was dyed with another colour before being allowed to run outside. Attempts were also made to manufacture soap, oil and cream in order to cover their activities, with attention being paid to the nature of the fat bought for these purposes in order to not contravene religious considerations.

It was soon realised that the acid-making process was slow and various apparatus purchases were made in order to scale up production. The revolutionaries also obtained ice from a restaurant to assist in the manufacture of guncotton using nitric and sulphuric acid.

Nitroglycerine was also produced in the factory, and the group also intended to make hydrocyanic acid from potassium cyanide, initially purchased in weak form from Gupta and later in a stronger concentration from elsewhere. The revolutionaries knew that hydrocyanic acid produced a very toxic gas and that an antidote would need to be available if those manufacturing it were not to suffer. It was the inability to procure an antidote that caused them to abandon the attempt.

Kailashpati had shown a bombshell to Jain and suggested to him that it would useful to produce something similar. Jain in turn used some engineering contacts in an attempt to produce the item but it came to nothing as the suspicions of his contacts were raised.

At the end of October 1929, Bhagwati Charan Vohra was introduced to Kailashpati. At that time, Vohra was an absconder in the Lahore Conspiracy Case. He asked to meet Azad in Delhi

Viceroy's train Soon after, Vohra criticised suggestions of killing relatively minor Raj officials and proposed instead to blow up a train carrying the viceroy, Lord Irwin. Yashpal was at that time living in the same Delhi house as Vohra and the two men were experimenting with arrangements of batteries to blow lightbulbs, thinking that such might be used as a primitive method of detonating guncotton.

Early in December 1929, Vohra and Yashpal secured the agreement of Azad regarding blowing up the Viceregal train, the rationale of the HSRA being that it would prevent a meeting between Irwin and Congress. However, on 22 December, Azad said in a meeting that, although he agreed with the plan, since Congress leaders such as Ganesh Shankar Vidyarthi were against it, it ought to be postponed. Vohra, Yashpal and Tiwari thought Azad was wrong but the decision eventually went in his favour.

Explanatory documents had been prepared for circulation after the now-aborted attack, along with two seals – one of them representing a hand grasping a sword and the other the monogram "H.S.R.A". – that were to be used on them. In view of the turn in events, the documents were destroyed but Vohra managed to retain the seals.

The attempt to blow up the train occurred some hours later on 23 December. According to S. K. Mittal and Irfan Habib, this "caused a commotion throughout the British Empire", following soon after the retaliatory murder of a police constable, John Saunders, and the bombing of the Central Legislative Assembly, both of which acts had involved Bhagat Singh. Police activity in Delhi became intense and the Congress leader, Mahatma Gandhi, who was generally firm in his condemnation of violence, congratulated the viceroy, saying

After a few days spent in hiding, Azad, Jain and Kailashpati left on foot for Nalgarha, around from the city. There they hid on a farm operated by sympathisers. On 1 January 1930, Azad and Kailashpati returned to Delhi. The following day, Yashpal also returned and he faced questions regarding why the train had been blown up in defiance of the decision of the meeting. Yashpal replied that he had yielded to the insistence of his companions, explaining that he and Vohra had gone to the scene on the morning of 23 December and that he had pressed the button that caused the explosion. They had worn military uniform so that no one should suspect them and had escaped by boarding a train headed for Ghaziabad. Azad was not at all satisfied with Yashpal's explanation.

The Philosophy of the Bomb leaflets

Two days after Yashpal arrived, Vohra returned and then Azad, Yashpal, Vohra and Kailashpati decided that in reply to a Congress resolution in praise of the Viceroy and in support of non-violence, a leaflet should be written by Vohra and distributed throughout India on the evening prior to "Independence Day", that is, 25 January 1930. Specifically, they intended to address a pamphlet issued by Gandhi – The Cult of the Bomb – which had criticised their methods.

In the event 500 leaflets were printed, entitled The Philosophy of the Bomb. These were then distributed on the intended day around educational buildings, to Congress workers and to press and news agencies. Other copies were posted to individuals, including Sir James Crerar, Home Member, Assembly, Delhi; Asaf Ali, the barrister; and Kamla Parshad Jain, of Baraut.

Plan to rescue Bhagat Singh and others

Later, there was a meeting in Cawnpore, attended by B. B. Tiwari, Satgur Dayal Awasthi, Vohra, Azad and Kailashpati. They decided to rescue the accused in the Lahore Conspiracy case by releasing a gas in court that would render everyone present senseless and permit the accused to be rescued. Aside from rescuing Kundan Lal, Kanwal Nath Tiwari, Bijay Kumar Sinha, Bhagat Singh, Rajguru, Batukeshwar Dutt, Ajay Kumar Gupta, and Sanyal, it had been decided that Mahabir Singh, Sukhdev Raj and Desh Raj were to be killed because they had made statements which had been of great assistance to the police. Further, Shiv Verma, S. N. Pande and three others (including Agya Ram) were to be given another chance to prove their sincerity, while the case of Gaya Prasad was to be tried by the Revolutionary Tribunal as it was uncertain whether he had made a statement or not.

Yashpal was charged with producing the gas to be used for the rescue attempt but found it impossible to do so. This caused a decision to effect rescue by a desperate attack on the court, for which the various conspirators undertook firearms practice away from Delhi. Funding for the rescue attempt proved to be a problem and a raid on the monthly wage delivery made to the Railway Clearing Accounts Office on the first of each month was considered.

But in the meantime, a sum of Rs. 3000 was given by Durga Devi, the wife of Vohra, for the purpose of carrying out the rescue plan and so, as there was no urgent need for money, the plan of robbing the Railway Clearing Accounts Office was given up. About the beginning of May, some blank forms were brought from Cawnpore, which were to be typed and distributed to the public after the rescue of the prisoners at Lahore.