Fears delays in awarding the contract to build the trains for the Government's Thameslink upgrade may have put the project in jeopardy.
Boris Johnson said he was backing David Cameron "all the way"
The Mayor of London has welcomed a new report calling for more financial autonomy for London.
A report out today claims that replacing Heathrow with a new hub airport would leave passengers, taxpayers and business worse off. It says a third London airport runway is essential if capacity is to be increased.
The study will be presented as evidence to the Airports Commission and argues against a new airport in the Thames Estuary, Isle of Grain or Stansted.
Earlier we spoke to John Holland-Kay, development Director at Heathrow.
Searches are being carried out by counter-terror police investigating the murder of Pakistani politician Imran Farooq, Scotland Yard said today.
Two residential addresses in north-west London are being examined and so far no arrests have been made.
Dr Farooq was stabbed to death outside his home in Edgware, north London in 2010 when he was ambushed on his way home from work.
He was a prominent member of the Pakistani political party MQM (Muttahida Qaumi Movement), and had been living in exile in the UK for more than a decade when he died.
In the weeks before his death he had been trying to raise his own political profile and had set up a Facebook page.
Police believe he was attacked by up to four men who had been seen near his house in Green Lane, Edgware, at various different times, apparently watching him.
Dr Farooq died from stab wounds and head injuries when he was attacked with knives and a house brick.
In the last three years investigators have interviewed eight people under caution and searched 10 addresses, but no one has ever been charged with the murder.
A £20,000 reward is available for information leading to the prosecution of Dr Farooq's killers.
Heathrow chief executive Colin Matthews said today:
"Britain already has one of the world's most successful international hub airports in Heathrow.
"Expanding Heathrow will put Britain ahead in the global race, connecting UK business to growth more quickly and at less cost to the taxpayer than any other option for new capacity.
"Heathrow is better located for passengers, business and jobs. Why build from scratch at a new hub when we can build on the strength that already exists around Heathrow today?"
Adding capacity at Heathrow would also be better for passengers and for jobs than anew hub airport at Stansted or in the Thames Estuary. Expansion could be delivered around seven years quicker than the time taken to build a new hub airport says the report by Heathrow bosses.
Creating a new airport would increase travel times for 90% of hub passengers, with the economic cost of longer journeys amounting to a possible £26 billion.
Adding capacity at Heathrow would also be better for taxpayers, with a new airport needing around £25 billion of public money, the report claims.
More than 76,000 people directly employed at Heathrow would face re-location or redundancy if Heathrow was replaced by a new airport.
The report also said that the area round Heathrow in west London was home to 202 of the UK's top 300 company headquarters.
Mayor Boris Johnson is one of the leading supporters of a new Thames Estuary airport and vehemently opposes the building of an extra, third, runway at Heathrow.
Labour backed the third runway plan in 2009 but the expansion was scrapped by the coalition Government, which has now set up an Aviation Commission under former CBI chief Sir Howard Davies to look into the whole question of airport capacity.
Today's report has been compiled by Heathrow Airport with architectural and planning consultants AECOM and Quod.
The report will form part of Heathrow's submission to the Davies Commission.The commission will publish its interim report by the end of this year and its final report in the summer of 2015.
The Mayor stepped on court at the Queen's Club yesterday in a charity match to help raise money for The Royal Marsden Cancer Charity.
The campaign hopes to give something back to the Royal Marsden Hospital which is currently treating British tennis player Ross Hutchins for Hodgkins Lymphoma.
Nearly a month on from the murder of Drummer Lee Rigby, religious groups in Woolwich have held a concert to remember him, and to show unity.
Organisers say they're aiming to bring people closer together.
A parliamentary committee has voted to allow film crews into the Houses of Parliament for the first time.
It opens the door to potential requests from large film companies hoping to film scenes in the historic corridors of Westminster.
Politicians hope to raise funds to help with costs of running the Commons, but many disagree with the idea.
Conservative MP for Harlow and the surrounding area, Robert Halfon said the plans would effectively turn Westminster into a 'theme park'.
The Russian President had to walk into Downing Street by the back steps because of a group of Turkish protesters outside the entrance. He seemed to take it in good humour.
The senior Liberal Democrat peer Lord Rennard's solicitors said in a statement:
We can confirm that Lord Rennard agreed to meet with the police and that he welcomed his first opportunity to refute the basis of allegations made against him.
We do not intend to make any further statement until the conclusion of the police inquiry.
Liberal Democrat peer Lord Rennard has been interviewed by the Metropolitan Police under caution after he voluntarily attended a south London police station by appointment today.