By Chirag Trivedi
BBC News, London
A covert security review of some of London's top museums has revealed priceless collections are at risk of theft, BBC News has learned.
The V&A's security was criticised
Security expert Will Geddes visited the British Museum, the V&A, the National Portrait Gallery and Wallace Collection last week.
He found weaknesses in areas like building access and use of technology.
The security audit found in one museum there were no CCTV cameras - apart from inside the gift shop.
Most of the museums said they were constantly reviewing their security and are always looking to improve it.
It follows a spate of high profile robberies from museums and galleries in Britain and across the world.
Mr Geddes, from International Corporate Protection (ICP) security firm, looked at several areas of security including use of technology like CCTV and access to areas of the building not available to the public.
April 2003: Theft of Picasso, Gauguin and Van Gogh from Whitworth Art Gallery, Manchester
August 2003: Theft of Da Vinci's 'Madonna With The Yardwinder' from Drumlanrig Castle, Scotland
August 2004: Theft of Munch's 'Scream' from Munch Museum, Oslo
4 October 2004: Theft of £60,000 of ceramics dating from the 15th to 19th Centuries stolen from the V&A
1 November 2004: Theft of rare medieval Chinese jewellery from the British Museum
He also assessed what he called social engineering - the ease with which staff were willing to give sensitive information.
The most vulnerable was found to be The Wallace Collection.
He found the walls were easily scalable, blind-spots in the CCTV coverage, and no security cameras inside the building - apart from in the gift shop.
He said one guard provided him with information about guarding cover, a contract firm responsible for the gallery, and security arrangements about another gallery in London.
The Canaletto Room - which has a collection worth about £30m - had no guard at all and there was little evidence of any anti-tamper devices near the paintings.
His report says: "In the Canaletto room the security which was evident was less than would be found in most retail shop environments with stock worth less than a quarter of that value."
A spokesman for the collection said Mr Geddes may not have seen many of the security measures which are "hidden", adding: "In light of recent events, the Collection has already undertaken a full risk assessment in relation to security and is in the process of making improvements."
At the Victoria and Albert Museum, Mr Geddes assessed the security of the 6th Floor Ceramics Section, scene of a robbery in October 2004.
He found a roof access door warning that unauthorised persons were not permitted was left unlocked allowing free access to the rooftop and could provide an escape route.
An electrical box was left open, allowing possible shutdown of power to the floor.
This could be easily used as a method to decoy security whilst another section was attacked, Mr Geddes said.
A main light-switch box was also exposed allowing the floor lights to be switched off.
Mr Geddes, who has worked in Iraq and South America, said a guard told him the area was potentially vulnerable as he was the only guard.
A spokesman for the V&A said they had carried out a thorough review in the last month and are currently implementing measures to improve security.
These gold earrings were among the stolen items from the British Museum
At the British Museum, Mr Geddes examined security in the Oriental Antiquities Gallery, where a robbery took place earlier this month.
The report said access to the gallery was extremely easy and it was difficult to determine what changes might have been made since the recent robbery.
On the guards he said they remained "somewhat static" at seated points.
But other security staff were both visible and proactive in their appearance, he said.
A spokesman for the British Museum said it is always looking to improve security and said the "safety of our collection is one of our key priorities".
At The National Portrait Gallery, Mr Geddes identified a potential risk point as the glass roof of the café section which could be reached via a street fence.
The National Portrait Gallery's security was praised
He adds that all conventional access routes to the museum had adequate security systems and there was a high presence of security guards in the venue at key conventional access points.
Sandy Nairne, director of the gallery, said: "Recent thefts in national museums are a matter of concern to everyone.
"We constantly review our security arrangements and have done so again in the light of these unfortunate incidents."
The only fault he found at The National Gallery in Trafalgar Square was the entry to the gallery through the Café and the rear stairwell.
The gallery refused to comment on the report.
Mr Geddes was asked to conduct the assessment to coincide with the launch of The Sancy Blood Diamond book by Susan Ronald which charts the historical thefts and intrigues surrounding the diamond, currently on display in The Louvre, Paris.