MORE than 4000 knives have been seized from visitors to the Scottish Parliament over the last three years.

New figures show that 1497 members of the public passing through the security entrance at Holyrood were asked to hand over blades last year alone.

In 2012, a total of 1380 knives were confiscated from the 400,000 visitors to the parliament, down on the 1497 taken from people in 2011.

On average, 28 knives per week are being confiscated by security staff at the building.

The figures also reveal that 645 other sharp objects, including scissors, corkscrews and screwdrivers, were taken from visitors over the three-year period.

The vast majority of the seized items are returned to the owners at the end of the visits. Many of the blades were pen or pocket knives and only those which are more than three-and-a-half inches long are not returned.

Less than 10 knives have been permanently retained by the ­Scottish Parliament police unit since 2005.

John Lamont MSP, the Scottish Conservatives' chief whip, said: "It does seem like an incredible amount of confiscations, particularly in relation to the number of visits Holyrood gets. You have to question why anyone would attempt to bring such items into a famously secure environment.

"However, it also shows security staff at the Scottish Parliament are doing an incredibly diligent and thorough job."

The £414 million Scottish Parliament building operates an airport-style scan and frisk system on visitors arriving at its main entrance. The Scottish Parliament has already spent £35,000 on stab-proof vests for Holyrood security staff, which they started wearing in 2011 amid reports that they could be vulnerable to attack.

Last year, a new £6.5 million security extension was opened at the building. The new entrance offers more space for screening and a baggage drop and bosses said it was given the go-ahead following security advice.

A Scottish Parliament ­spokesman said: "For the safety of all, the Parliament does not allow visitors to carry certain sharp objects such as pen-knives or scissors while they are in the building, even if it is perfectly legal to do so in public."

Police Scotland said 20 crimes had been reported at the parliament over the last three years, but none of them involved an offensive weapon.