Former top bankers at Barclays who will go on trial over the bank’s arrangements with Qatar during the financial crisis now face new fraud charges.

The UK Serious Fraud Office was given permission on August 1 by Mr Justice Popplewell to amend its indictment against the three men in the high-profile case, according to a document made public. The defendants now face substantive fraud charges in addition to those of conspiracy when their retrial starts at London’s Old Bailey in October.

Barclays turned to Qatar and other investors twice in 2008 to stave off government control, even as other UK high street rivals were bailed out. It undertook two emergency cash calls, raising a total of £11.8bn.

But the SFO alleges that £322m worth of side deals with Qatari investors — including the prime minister of the Gulf state at the time, Sheikh Hamad bin Jassim bin Jabr al-Thani — were not properly disclosed to the market.

Facing retrial are Roger Jenkins, once the bank’s rainmaker in the Middle East who negotiated the two capital calls; Tom Kalaris, who led the bank’s wealth division; and Richard Boath, the former European head of the financial institutions group of Barclays’ investment bank.

The three deny the charges, which carry a maximum 10-year sentence.

The new indictment has all three charged with substantive fraud, over the first capital raising Barclays undertook in June 2008, as well as conspiracy to commit fraud by false representation. Mr Jenkins faces an additional pair of charges over the second fundraising in October 2008.

The case, which the SFO began investigating in 2012 and has cost more than £15m in special taxpayer funds, has been whittled down from its starting point. The SFO had initially charged Barclays with unlawful financial assistance by providing Qatar with a $3bn loan just as a second round of fundraising from the Gulf state was closing. Those charges were scrubbed last year before trial.

John Varley, the bank’s chief executive at the time, was also charged alongside Mr Jenkins, Mr Kalaris and Mr Boath but he was acquitted in April by the first trial judge, Mr Justice Jay, on the basis that he did not have a case to answer because the SFO had not brought sufficient evidence against him. That decision was upheld in June by the Court of Appeal.

Mr Varley was the first chief executive of a major bank in the world to face a jury over events during the financial crisis.