File photo dated 24/04/12 of a G4S logo, as under-fire Olympics security firm G4S has barred top bosses and senior executives from attending corporate hospitality jollies in light of its security fiasco for London 2012.

The London Olympics security shambles presided over by G4S cost the firm £50m, it has been revealed.

Thousands of security posts went unfilled by the security giant, last month.

Armed forces personnel had to step into the breach in what was a huge scandal.

Many soldiers had only recently returned from arduous tours of duty in deadly war zones.

The cost of the failings by G4S saw company profits slide sharply to £61m from £151m a year earlier.

hief executive Nick Buckles was hauled before a parliamentary committee to explain himself.

But one G4S shareholder warned that appearance risks harming UK business.

Neil Woodford, investment manager at Invesco Perpetual, labelled the inquisition a “medieval persecution.”

“If this is the way Parliament wants to treat business, please Parliament, don’t be surprised when businesses decide this isn’t the country for them.”

The behaviour of MPs was “incredibly damaging for the economy and this country”, he claimed.

“Chief executives will have watched that hearing with horror,” he added. “It’s disgraceful and very damaging. Companies will be thinking twice about bidding for any government work.”

G4S are due before a parliamentary committee for the second time next month.