Britain’s biggest arms company, the BAE Systems, which had been at the centre of a long-running worldwide bribery scandal is to pay £286 million in fines to British and American authorities after being forced to admit criminal charges following a nearly eight-year-long trans-Atlantic investigation into its arms deals with Saudi Arabia, Tanzania and several central European countries.

The deal, which will see an end to further investigations into allegations of corruption, provoked fury among anti-arms trade activists who argued that the company had been let off lightly by being allowed to plead guilty to the lesser charge of accounting irregularities rather than corruption.

“Ultimately the charges that we see admitted are administrative charges, not charges of corruption,” said Norman Lamb, a senior Liberal Democrat MP, who led a campaign.

The Campaign Against the Arms Trade said it was “outraged and angry” that the BAE had got away with a “tiny” fine.

Under the deal, announced on Friday, the company will pay more than £250 million to America where it was accused of “wilfully misleading” investigators over payments it made to win contracts in Saudi Arabia and a number of central European countries.

In Britain, it would pay £30 million over allegations of wrongdoing in relation to a deal to supply a radar system to Tanzania.

Campaigners called for reopening of investigations into allegations that it paid millions of pounds in bribes to win a multi-billion pound contract to sell arms to Saudi Arabia in the 1980s.

An investigation by the Serious Fraud Office was dropped in 2006 following intervention by the then Prime Minister, Tony Blair, who argued that Riyadh had threatened to stop sharing terror-related intelligence if the investigation went ahead.