Sept. 16 (Bloomberg) -- A junior member of the U.K. government resigned today, becoming the first minister to walk out in protest at the leadership of Prime Minister Gordon Brown.

The departure of David Cairns, a minister in the Scotland Office, increases pressure for a contest to replace Brown. More than a dozen Labour Party lawmakers are demanding a ballot, saying the party is doomed at the next election unless Brown steps aside.

``The issue of leadership does need to be addressed,'' Cairns said today on BBC News 24. ``I'm not part of any plot. It was incompatible to remain as a member of a government, but to fundamentally have such a different opinion on such a key issue as this.''

Brown accepted the resignation, saying ``the exercise of government demands collective responsibility,'' according to a statement released by his office in London.

Labour, almost neck-and-neck with the opposition Conservatives in opinion polls when Brown took over from Tony Blair in June 2007, now trails by 20 percentage points as the economy teeters on the brink of a recession. The next election has to be held by mid-2010.

Labour, with 349 lawmakers in the 646-member House of Commons, has a majority of 62 seats over other parties combined after losing two formerly safe constituencies to the Conservatives this year. Labour was trounced in local authority elections in May.

Call for Change

``We can change ourselves in power, by listening to voters who want us to act, and acting firmly and progressively in these times of economic turmoil,'' Labour lawmaker John Cruddas wrote today the the House magazine, a parliamentary journal. ``We still might not win. But if we do nothing, then we will certainly lose.''

The resignation deepens the crisis engulfing Brown. Since Friday, he has fired two Labour members of Parliament from government jobs in an effort to reassert his authority, and a third stepped down after calling for a leadership ballot.

While the rebels are far from the 70 votes needed to trigger a challenge to Brown, they argue that other lawmakers support them and are afraid to come forward. They aim to build momentum ahead of Labour's annual conference next week in the hope that Cabinet members will come out and challenge Brown.

`Another Blow'

``This is another blow, strengthening the call for change,'' said Wyn Grant, a professor of politics at Warwick University. ``The feeling at the top of the party, among the senior Cabinet members, is that it is premature to do this ahead of conference, that Brown should be given his chance to face the party.''

Labour's ruling executive today rallied behind Brown, rejecting calls for a vote and refusing to send out leadership nomination papers.

``Internal procedural debates will not divert the Labour Party'' from the job of government, Dianne Hayter, chairman of the 33-member National Executive Committee said in an e-mailed statement.

Cairns, 42, was a former researcher to Siobhain McDonagh, who was fired as an assistant whip in the House of Commons after calling for a leadership challenge.

`Loyalist'

A former Catholic priest, Cairns needed her help to get elected to Parliament in 2001. An 1801 law prevented former Catholic priests from sitting in the U.K. parliament, until McDonagh helped get it overturned. The ``Almanac of British Politics'' describes Cairns as ``a chubby, benign-looking loyalist.''

Brown attended some of the NEC meeting in London today. He held his weekly talks with Cabinet colleagues this morning, where discussion of the economy dominated the 45-minute meeting, according to his spokesman, Michael Ellam.

Brown's supporters argue that a leadership contest, which would take at least a month, would only destabilize Labour further.

Chancellor of the Exchequer Alistair Darling said in a BBC interview today that he had every confidence in Brown, while the Labour chairman of Parliament's Treasury Committee said Brown was the best person to lead the country through the financial crisis.

``Who will people put in Downing Street that will provide a magic wand? There is no one,'' John McFall said in an interview with Bloomberg Television. Brown has a ``tremendous'' record after a decade as finance minister. ``Rather than throw anybody overboard, we need everyone on board to ensure we get through these turbulent times.''

To contact the reporters on this story: Mark Deen in London at markdeen@bloomberg.net

Last Updated: September 16, 2008 12:39 EDT