A former SAS officer who passed secret details of MPs’ expenses claims to The Daily Telegraph broke cover last night to insist he had “no regrets” about the leak that has rocked Westminster.

John Wick said the release of the information over the last fortnight had exposed the parliamentary expenses system to “its rotten core”.

Mr Wick, the head of a corporate intelligence company specialising in the release of hostages in war zones, was named as an intermediary between an anonymous parliamentary source and the Telegraph. He claimed that the details had not been stolen, and was withering about the “lax” security procedures in the Commons for handling the claims. Mr Wick contacted several newspapers and eventually passed over more than one million pages of unedited receipts to the Telegraph. The paper is rumoured to have paid between £60,000 and £70,000 for the details, but has consistently refused to disclose whether any money changed hands.

Download the new Independent Premium app Sharing the full story, not just the headlines

Mr Wick was unrepentant last night over his part in getting the uncensored claims – rather than the censored version being prepared by the Commons – into the public domain.

He said: “Parliament will be a better place, society will be a better place.

Sometimes a marker has to be put down. The public has put a marker down. It’s good.”

He disclosed he supported the Tories, but said he was not motivated by party-political concerns. “This was a scandal across the political spectrum with some Conservative MPs’ behaviour as reprehensible as their Labour counterparts. The public release of the information had to be thorough, across every party, and the Conservatives would have to accept the consequences with the other parties.”

He said he was conscious of the risks he was running, but had decided to act after the public was frustrated in its attempts to learn about politicians’ expense claims. He said: “We’ve all had concerns about the expenses purely because of how they’ve handled our requests for information. We’ve reached a stage in society where they want to know everything about us – I think we’re entitled to know about them.”

Mr Wick said he had been contacted in March about a hard drive containing all MPs’ expenses claims of the past four years. He said his contact, who he did not identify, had indicated that “those directly involved in processing the raw data were shocked and appalled by what they were seeing”.

He went on: “I was assured that the data was not stolen, but that it was an unregistered copy that had been produced as a result of the lax and unprofessional security procedures used in the House of Commons”

He claimed: “I do not believe the parliamentary staff handling the data were security cleared and people working on the information were never checked when leaving, nor did they work in a secure environment. All of this must have been known by the Speaker’s office, which failed to act and be responsible for the data and those working on it.”