Security for the world leaders attending next month’s G20 summit in London is being stepped up amid fears that violent protesters will find out where they are staying.

Police have received intelligence reports that hotels and other buildings could become the target of “guerrilla-style raids” by anti-globalization groups and are increasing the number of close protection officers that will be stationed at each location.

All police leave has been cancelled in London for the first two days of next month – the summit is on April 2 – and thousands of uniformed officers will be on the streets to prevent legitimate protests from being hijacked by violent activists after indications that there will be the worst public disorder in a decade.

Anarchist groups and environmental activists are already collaborating on a series of demonstrations, which are being advertised with slogans such as “Storm the Banks” and “Bash a Banker”. One website urges demonstrators to “express their rage” and promises “a day of f***ing up the summit and other adventures” on April 2.

The security operation to protect politicians attending the event will be the largest seen in Britain since the G8 met at Gleneagles in July 2005. Some of Scotland Yard’s key security personnel were stranded in Scotland when the July 7 suicide bombers detonated their devices and killed 52 people on the London Underground and on a bus as the meeting took place.

The Times understands that there is no intelligence pointing to a terrorist attack to coincide with G20, but that a detailed anti-terrorist contingency plan has been drawn up.

A senior source said: “We could never rule out the idea that the G8 event might have been the inspiration for the 7/7 terrorists. There’s no intelligence of an attack now but we would be foolish if we weren’t thinking along those lines – you cannot afford to discount any possibility.”

Click here to read the full report from the Times.