Emails between bank staff and owners of small businesses who bought interest-rate hedging contracts will be evidence in mis-selling claims totalling up to £1bn, the Gazette can reveal.

Norton Accord, the company that has secured funds to launch up to 4,000 cases, said that client emails are among the criteria it is using to assess the strength of optional claims.

Meanwhile, claimant lawyers have accused some banks of deploying ‘strong-arm tactics’ against customers who have raised mis-selling of hedging contracts as an issue.

Chris Hale of Bracewell Law, whose firm is advising clients on funded claims arising from hedging contracts, told the Gazette banks were taking a ‘tough line’. ‘Where clients are raising mis-selling as an issue, it seems to be a tactic – banks are not above withdrawing facilities from those customers,’ he said.

Hale also accused the banks of delaying tactics, such as ‘providing transcripts and emails in their possession as late in the process as they can’. The ability to fund cases has been important, he added, where banks might ‘rely on our clients running out of money’.

Paul Crawford, director of Norton Accord, said he expects banks ‘to draw these cases out, but then settle before they reach court’. Norton Accord panel solicitors will issue the first proceedings in the next seven weeks, with each case expected to last 12-18 months.