Michael Martin took over as Speaker in 2000 from Betty Boothroyd
House of Commons Speaker Michael Martin has announced he will stand down on 21 June.
His decision came after he found himself at the centre of yet another political storm.
The Speaker had come under fire for his own expenses claims in the past, but it was his reaction to the allegations levied against others that provoked harsh criticism.
He told the Commons there must be a police investigation into the source of the leak to the Daily Telegraph.
When other MPs - Kate Hoey among them - suggested that the issue of the expenses themselves, rather than their release, was paramount, Mr Martin reacted angrily, saying he had already heard Ms Hoey's "pearls of wisdom on Sky News".
Since then calls grew for the Speaker to step down with Lib Dem leader Nick Clegg the most senior politician to join the campaign.
He has accused Mr Martin of being a "dogged defender of the status quo", and a major obstacle to greater "transparency and accountability" in the expenses system.
Mr Martin's decision to step down came after the dust had barely settled on his last bout of controversy.
In December, after the Met Police's anti-terror squad raided the office of Tory MP Damian Green, Mr Martin was accused of failing to protect both MPs' rights and the power of Parliament to hold government to account.
Keep order during debates
Ensure House rules obeyed
Chooses MPs to speak
Can suspend sittings
Protects interests of minorities
When the Speaker revealed that officers had not had a warrant to search Mr Green's office, the Commons erupted and Mr Martin found his head on the block.
He insisted that while he had known about the raid in advance, he was not aware of the absence of a warrant and resisted all calls to step down.
That storm in the end was weathered, just one in a long line.
For their part, the Speaker and his supporters argued that he faced an unprecedented campaign of snobbery and slurs since taking on the job.
With his Glaswegian brogue and background as a sheet metal worker and trade union official, he was quickly dubbed "Gorbals Mick" by some Tories and members of the press.
Mr Martin is MP for Glasgow North East but, as Speaker, he ceases to represent any party and is expected to be neutral - but there were mutterings that he favoured former Labour colleagues.
First elected in 1979 as MP for Glasgow Springburn, the teetotaller was seen as on the right of his party and a social conservative on matters such as abortion and homosexuality.
After his elevation to the post of Speaker in 2000, he began with a press conference - provoking critics to say he had broken the convention of keeping a distance from the media.
The first Roman Catholic to serve in the role since the Reformation, Mr Martin - who underwent heart surgery in 2005 - has not been shy to dispose of other centuries-old traditions.
He did away with the tights worn by Speakers in favour of dark flannel trousers and continued the precedent set by his predecessor as Speaker, Betty Boothroyd, by dispensing with the traditional wig. He also appointed the first PR adviser to the House of Commons Commission.
The Speaker is paid a salary roughly equivalent to that of a cabinet minister and is expected to keep order, ensure balanced debates and call MPs to speak.
But the first comments alleging bias by Mr Martin came just one month in the role.
Mr Martin expelled pro-Israeli Tory MP John Butterfill from the Commons, after he complained he had not been called to speak during a debate, while six pro-Arab MPs had been.
In October 2001, he had to apologise after speaking up in favour of Home Secretary David Blunkett's abolition of the voucher scheme for asylum seekers.
Mr Martin also faced attacks from the government benches.
In February 2002, he told off Tory leader Iain Duncan Smith, and then prime minister Tony Blair, for raising what he described as party matters during prime minister's questions.
In the ensuing row, it was reported that Mr Martin felt he was being undermined, because of his background, with each slur "an attack on every working class person from Clydeside".
Later Labour MP Tam Dalyell said: "All this stuff I read about 'Gorbals Mick' is odious. What the man is trying to do is do the job of Speaker properly."
Charles Clarke, then Labour Party chairman, was quoted in the Times newspaper in 2002 as saying Mr Martin had "become an embarrassment" - but he later denied saying this.
In 2006, Mr Martin provoked uproar in the Commons by stopping Tory leader David Cameron asking Tony Blair whom he wanted as "his successor".
Mr Martin insisted prime minister's questions was meant for discussing government business, not party matters. Mr Cameron called the decision "bizarre and extraordinary".
Last year, the Speaker's own allowances came under the spotlight - including claims he had flown members of his family in business class from Glasgow to London for a New Year break, using air miles gained from official trips.
Newspapers went on to report that Mr Martin had claimed £17,000 a year for his home in Scotland and £7,500 in costs for using the property as an office.
The figures had been publicly declared already and there was no suggestion he had used his allowance incorrectly.
On 23 February, Mr Martin's spokesman Mike Granatt announced he was resigning over his handling of a Mail on Sunday story about the Speaker's wife using taxis for shopping.
He said he had quit for "ethical reasons" after "unwittingly" giving out the wrong information to a journalist.