Constituents could become reluctant to ask their MP for help with problems because they fear personal confidential information could be seen by others, according to a Kent Labour MP.

Dover MP Gwyn Prosser, a member of the Home Affairs select committee, said the arrest of the Ashford MP Damian Green as part of a police investigation into a series of Home Office leaks, risked undermining the relationship between MPs and their constituents.

As part of the the police investigation, computers containing details of Mr Green’s constituency casework and correspondence were taken from his House of Commons’ office.

There was also a search of his constituency office, although it is understood no papers were taken away from there.

Mr Prosser said: "Constituents are absolutely right to be concerned because up until now we have been able to say to them that whatever information they share with us is totally confidential and will stay confidential and that no outside agency will ever have access to that. That has now been undermined by what has happened over Damian Green," he said.

His comments echo the view of Harriet Harman, leader of the House of Commons, who said it was important MPs were able to do their jobs properly.

She said: "We have got to be sure that whilst MPs are not above the law, that actually they are able to get on with their job without unwarranted interference by the law. These are very, very big constitutional principles, we have to make sure they are protected."

Folkestone and Hythe MP Michael Howard has also voiced his concerns over constituents’ privacy, pointing out that in some cases, constituents called on MPs to take up concerns over the police.

Mr Green, who has emphatically denied any wrong-doing, was today back at work at Westminster, according to his constituency agent.