Sats papers delivered to newsagent's

National curriculum test papers that should have been sent to a secondary school on the Isles of Scilly ended up being delivered to a news-agent's instead.

The test papers for 14-year-olds, which were meant for Five Islands School – the one secondary school on the islands – did not reach the school until the newsagent passed them on.

According to the Qualifications and Curriculum Authority, the Government's exams watchdog, the address on the box of Sats (standard assessment tasks), became obscured while it was being transported to the island by ferry.

Boxes of books addressed to the newsagent had also been on the ferry – and the test papers were delivered to it instead. They have now been placed in a locked safe at the school and – because their security has not been breached – there is no reason they cannot be used.

The blunder is the second controversy to hit this year's national curriculum tests in 24 hours and it has heightened fears on the security of the tests. On Thursday, police confirmed they had been called in to investigate the selling of tests for 14-year-olds on the black market for £100. Staff from the QCA say they have "contingency plans" if the sale of the tests proves to be widespread rather than an isolated incident.

Those include withdrawing them and substituting reserve tests, which QCA headquarters staff have already drawn up, ready to be issued.

The tests, for two million pupils aged 7, 11 and 14, will start in schools in the first week in May when they reopen after the Easter holiday.