Labour peer Baroness Uddin has escaped prosecution following a police investigation into her parliamentary allowances.

The Baroness gave the address of a flat in Maidstone off Wat Tyler Way as her main home and then claimed subsistance allowances thought to total in the region of £100,000 for staying at her family home in East London.

But the Director of Public Prosecutions Keir Starmer has decided it would not be possible to bring a successful prosecution because there was no legal definition in the House of Lords’ expenses scheme for what constituted a main residence.

Mr Starmer said: "Members of the House of Lords are entitled to claim certain expenses under the House of Lords’ expenses scheme and one of those is for ‘night subsistence’. That allowance can only be claimed if a peer whose ‘only or main residence’ is outside London stays ‘overnight’ in London because of House of Lords business.

"The allegation against Baroness Uddin was that she had claimed ‘night subsistence’ for overnight stays in London, after attendances in the House of Lords, to which she was not entitled.

"Although she had nominated a flat she owned in Maidstone as her ‘only or main residence’, it was alleged that ‘her only or main residence’ was in fact a house in east London.

"It was always recognised that the definition of ‘only or main residence’ under the House of Lords’ expenses scheme would be critical to any possible criminal proceedings against Baroness Uddin. However, ‘only or main residence’ is not defined in the House of Lords’ expenses scheme itself; nor is it defined in legislation."

Mr Stramer pointed to a statement by the Clerk of the Parliaments, Michael Pownall, in which it was stated that it was up to "members to designate an address as their main residence as they see fit".

Last month, Mr Pownall stated: "A main residence has to be visited with a degree of frequency: in the order of at least once a month, over the year, when the House is sitting."

Mr Starmer said: "On that interpretation, in any criminal proceedings, it would be necessary for the prosecution to prove that any peer in question had not even visited the address they deemed their ‘only or main’ residence once a month.

"That presents a very real difficulty and I have advised the Metropolitan Police to take no further action."

Baroness Uddin could still be disciplined by the Lords authorities if they find she breached guidelines for allowances.