More than 649,000 alerts relating to potential drug and tobacco smuggling into the UK were deleted from a Government system for border controls without being read, an inspection has found.
The deletions had a "significant impact" on the ability of staff at the border to seize banned goods and arrest those responsible for smuggling them into the country, the Chief Inspector of Borders and Immigration John Vine said.
This amounted to three quarters of all the customs work completed at National Border Targeting Centre (NBTC), the hi-tech hub where watch-list checks on passengers entering and leaving Britain are carried out, his report said.
Mr Vine uncovered the deletions as part of an inspection into the multimillion- pound eBorders programme, set up by the Home Office 10 years ago to prevent passengers from travelling where they were considered a threat to the UK.
More top news
Anything less than a Spurs win at Stamford Bridge tonight will mean Leicester City take the championship.
Parents will be taking their children out of school tomorrow in an unprecedented "strike" against compulsory exams for six-year-olds.
Sam Vokes sealed Burnley's return to the Premier League at the first attempt with a brilliant headed winner against QPR.