Prime Minister David Cameron and Deputy Prime Minister Nick Clegg held an unprecedented press conference Wednesday to outline the policies their government will follow over the next five years.

The Downing Street news conference was the first opportunity for the new coalition government's two key leaders to say what direction their policies will take.

Cameron's right-of-center Conservative party is the larger player in the alliance with the much smaller Liberal Democrat party led by Clegg.

Nevertheless, there has been considerable compromise on policy from both parties.

The most significant concession was from the Liberal Democrats, who have agreed to the Conservative timetable of cutting public spending now in order to immediately start reducing the record public sector borrowing debt.

At the press conference, Cameron outlined the broad banner behind which his coalition would march. The prime minister said that the alliance represented a "historic and seismic shift" in Britain's political landscape.

"It will be an administration united behind three key principles: freedom, fairness and responsibility," he said. "And it will be an administration united behind one key purpose ... the strong and stable and determined leadership that we need for the long term."

Clegg underlined the new start the government was making and its radical credentials.

"This is a new government, and it's a new kind of government, a radical, reforming government where it needs to be and a source of reassurance and stability at a time of great uncertainty," he said.

Clegg will have responsibility for political and electoral reforms. The coalition is now committed to a referendum on electoral reform, specifically the Alternative Vote system whereby voters can choose two candidates in an election and rank them No. 1 and No. 2.

If candidate No. 1 gets eliminated, the vote goes to candidate No. 2. The system ensures that the winner in a vote has at least 50 percent of the votes cast.

The measure does not go far enough for Liberal Democrats, who have long campaigned for proportional representation, and it was one of the major compromises with which they agreed.

Clegg will also be responsible for reforming the House of Lords, the parliament's second chamber. A series of rolling elections every five years, with winners serving for 15 years will replace the current members of the Lords. The small number of hereditary peers will not be replaced when they die.

A government can still be brought down with a vote of no confidence but it will need 55 percent of the vote rather than the current majority of one.

There also will be legislation for fixed-term parliaments of five years. Currently it's up to the prime minister to choose the date of the election, with a maximum term of five years.

There were also agreements concerning the European Union. This was a tricky area for the Conservatives, who have strong eurosceptic tendencies while the Liberal Democrats are strongly pro-EU.

The agreement said there will be no further transfer of sovereignty to the EU from the British parliament, and also a commitment that the country would not join the euro in the lifetime of the next parliament.

On defense, there will be a War Cabinet for the war in Afghanistan, and a new National Security Council to coordinate responses to security threats such as terror attacks.

An already-planned strategic defense review will be held as soon as possible, and the renewal of the submarine-based, independent, strategic nuclear force will go ahead.

The controversial personal identity card plan introduced by Labour, which was seen by some as an intrusion into privacy and infringing civil liberties, will be axed. There also will be safeguards on the use of DNA details for civil liberty reasons.

The Liberal Democrats compromised on their plan for amnesty for illegal immigrants and there will now be a cap on immigrants from outside the EU.

On the environment, they also compromised on their opposition to new nuclear power stations, and a building program will probably go ahead to replace the country's remaining old stations.

However, there was also an agreement that no new coal-fired power stations will be built without carbon capture.

On other environment issues, there will be a green investment bank, a tax on planes, a commitment to build a high-speed rail network and a ban on new runways at the three major London airports.

On the crucial economic front, there will be an emergency budget within 50 days, and next year's planned tax rise in National Insurance of 1 percent will not go ahead. In addition income tax allowances will rise for the lowest paid, which was a specifically Liberal Democrat policy.

Banks will be reformed, and there will be legislation to stop high bonuses for bankers.

On education, there will be investment to lower the size of classes in schools for children from poor backgrounds, and the flagship Conservative policy of allowing parents or groups to set up their own state-funded schools looks set to go ahead.

The Liberal Democrats hold important but not always key places in Cameron's Cabinet, including Clegg himself as deputy prime minister. Other Liberal Democrats are the Scottish secretary Danny Alexander; the first secretary to the treasury David Laws, a key role in the extensive cuts that will have to be made to reduce public spending; Chris Huhne as energy secretary; Vincent Cable as business secretary.

The three big offices of state, finance, foreign affairs and the home office are held by Conservatives. Cameron's senior lieutenants George Osborne and William Hague get the chancellor of the exchequer and foreign secretary respectively and Theresa May, the highest ranking woman, fills the home secretary post.

The coalition has now committed itself to five years in government. At this very early stage in the political wedding, it looks like a happy marriage is in prospect. But the domestic bliss could turn sour when tough decisions over cuts and budgets have to be made, and that will come very soon indeed with an emergency budget pencilled in within the first 50 days.