Video footage taken of the Palace of Westminster appears to show an unidentified man on the roof. It is not known if this is a member of the fire brigade.
A man has scaled the roof of House of Commons while fire fighters and police attend the scene.
Emergency services were called to the Palace of Westminster tonight after a man was seen on the roof. A Scotland Yard spokeswoman said officers were on the scene to deal with the incident.
She added: "At 9.15pm officers were made aware of a man trespassing on the roof at the Palace of Westminster. London Fire Brigade and London Ambulance Service are in attendance."
There was no immediate information as to why the man was there. The roof has been the scene of stunts by campaign groups in the past, including by protesters demonstrating against plans for a third runway at Heathrow Airport in 2008, and Greenpeace a year later.
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Ed Miliband has suggested the public's confidence and trust in the political system will be undermined unless the uncertainty over MPs' pay is resolved.
Mr Miliband has said all three party leaders should meet the head of the Independent Parliamentary Standards Authority to voice their concerns over the planned 11 per cent pay rise.
Ed Miliband has said all three party leaders should make clear their opposition to the head of the Independent Parliamentary Standards Authority (Ipsa)'s expected recommendation of an 11 per cent pay rise to MPs tomorrow.
In a letter to David Cameron, the Labour leader wrote: "I believe the three party leaders should meet Sir Ian Kennedy tomorrow to make clear our view that we cannot go ahead with the current proposition."
Prime Minister David Cameron has said he thinks it would be "simply unacceptable" for MPs to get a pay rise "at a time of public sector pay restraint".
Responding to Ed Miliband's question on a proposed pay rise "many times above inflation" in 2015, Cameron said there was agreement across the three main political parties on this issue.
He also said the Independent Parliamentary Standards Authority - which is proposing a rise worth £7,600 - needed to "think again".
The Deputy Prime Minister's office has responded to Ed Miliband's call for cross party talks to block the planned pay rise for MPs.
Sources point out that there is already cross party agreement on the issue: all three party leaders have publically expressed their opposition to the reported 11 per cent hike in salary.
Nick Clegg's aides also point out that the Independent Parliamentary Standards Authority does not publish its recommendations until Thursday, so it would be wrong for politicians to get involved in a process - which is rightly independent of politicians - before the announcement has been made.
Earlier Downing Street declined to say whether David Cameron is ready to accept the expected above-inflation pay hike for MPs.
The PM's official spokesman told a regular Westminster media briefing:
I don't believe Ipsa have made a formal proposal yet. Any proposal that they make will be reviewed in mid-2015.
The Prime Minister's long-standing position is that the cost of politics should go down, not up. He doesn't think that MPs' pay should go up while public sector pay is being restrained.