BAE Systems and Saudi Arabia are negotiating a new £1bn contract for 60 Hawk trainer jets, despite the UK Serious Fraud Office's (SFO) recent investigation into allegations of corruption.
Opposition MPs have questioned whether the new deal was a factor when the SFO investigation was dropped at the government's request only six months ago, UK newspaper The Independent reports.
Liberal Democrat health spokesman Norman Lamb says it is possible the huge deal was dangled during the inquiry.
"One question is whether this was envisaged at the same time that the British prime minister advised against the investigation continuing," Lamb says.
"It certainly needs to be pursued. Particularly if there is a link between this contract, supply of work, and the decision in December."
BAE Systems did not comment on the negotiations, or Mr Lamb's accusations.