Finger of blame is pointed at Serjeant

Commons Speaker Michael Martin told MPs that it was the Commons security chief, not himself, who gave detectives permission to search shadow immigration minister Damian Green's parliamentary room.

The failure to insist officers produce a warrant before being allowed in has outraged MPs and left Mrs Pay fighting for her job.She made history in January this year when she was the first woman to be appointed Serjeant.

But she will almost certainly be remembered for what many MPs see as a breach of Parliament's privileged position to protect constituents and hold the Government to account.

The Serjeant, whose post dates back to 1415, is responsible for security within the Commons.

But Mrs Pay has never managed to shrug off questions over her suitability with reports the Queen refused to grant her an audience after her appointment. She took over from Sandhurst-educated Major-General Peter Grant Peterkin, who is said to have clashed with Mr Martin.

Mrs Pay took over on a salary said to be about half what her predecessor received and a tighter remit on her job.

Dressed in traditional uniform, the Serjeant is the head of the House's security team.

Ceremonial duties involve carrying the House of Commons mace for the Speaker's procession. The Serjeant, or a deputy Serjeant, sits in the chamber and is responsible for security during the sitting. Mrs Pay has worked at the Palace of Westminster since 1994, when she was head office keeper, and has served as an assistant Serjeant at Arms since September 2004.

Before joining the Commons service, she was deputy director of the Department of Employment's Technical and Vocational Education Initiative.

She has also worked as business manager to a medical practitioner and executive officer in an advertising agency.

She is married with two daughters and lives in London.