A spokesperson for G4S said the firm had not been provided with the results of the initial audit of the government electronic monitoring contracts with the government, despite requesting the report.
They said an internal investigation, with external help, found no dishonesty in the tagging contracts.
More top news
See how your area fares.
The world's first ever 'hole in the wall' was installed in Enfield, north London, on June 27 1967.
America says it has "identified preparations" for an attack similar to that which killed at least 86, including 30 children, in April.