MP Julian Brazier is defending his decision to join a parliamentary group hit by a lobbying scandal which has all but ended the career of a fellow Tory.

The MP for Canterbury and Whitstable was dragged into the latest cash-for-questions scandal to hit Westminster, after he was named as one of the members who joined the group on Fiji.

Mr Brazier shared an office with Patrick Mercer, the MP who took £4,000 from undercover reporters posing as lobbyists who said they wanted to overturn sanctions imposed on the country due to its human rights record.

Mr Mercer resigned the Conservative whip on Friday after being exposed by The Daily Telegraph and the BBC’s Panorama programme. He boasted to undercover journalists that he had persuaded 18 MPs to join the all-party parliamentary group (APPG) on Fiji, including Mr Brazier.

But Mr Brazier has defended his decision to join the APPG, calling it common practice to support the setting up of such groups.

Mr Brazier, who has been in his seat for more than 20 years, said: “It is common practice to support the setting up of all party groups by colleagues.

“Without colleagues’ support I would never have got the 20 names I needed for the three separate campaigning groups I set up on adoption, adventure training and reserves.

“I share an office with Patrick Mercer and so agreed to join, but not to support any specific agenda.”

Mr Brazier is one of several MPs from both major parties who have admitted they joined the APPG on Fiji.

But Mr Mercer appears not to have disclosed to them that he took payment from lobbyists for Fiji, which is a breach of a ban on MPs undertaking paid advocacy on behalf of clients.

The groups can be formed by any MP who persuades 19 colleagues to join. More than 400 exist but comments to the undercover reporters by Mr Mercer suggest some can be seen as an excuse for trips to exotic destinations involving little or no work.

But Mr Brazier added: “I have never lobbied for the Fijian government or any other Fijian interest, apart from Fijians serving in our forces. I have always been scrupulous about upholding Parliament’s advocacy rule.”

The latest Commons register of interests shows that 60 MPs declared they had been on trips abroad in connection with APPGs, with costs amounting to £175,000 paid by third parties including charities, banks and oil companies.

The Canterbury and Whitstable MP said he would not be against overseas visits if they were for a purpose, but explained the only trip he had taken with an APPG was a trip to wartorn Beirut.

Critics say the system lacks transparency and that there is no way of knowing of the involvement in groups of lobbying companies, or of the public assessing whether the trips are for legitimate activities, such as promoting business overseas, or essentially for free holidays.

But Julian Brazier has defended the groups, saying: “I strongly support the existing structure. The problem here is about lobbying and corruption. It is not a problem with all party groups. They are an extremely important vehicle for getting things done.”