Ethical bank Triodos is to launch an online cash ISA offering savers a 2.5 per cent return, which includes a 12 month bonus of 0.75 per cent.

The 90 day notice account, available from Monday February 27, can be opened with a minimum of £10.

Triodos said there has been a surge of interest in ethical ISAs since the economic downturn.

Research by the bank revealed a 71 per cent rise in ISAs between April 2007 and May 2011, compared with the rest of market which saw an increase of 52 per cent during the same period.

Huw Davies, head of personal banking at Triodos Bank, said: “We believe savers should be able to have a competitive rate but also a social and environmental return.

“Many savers are concerned about where their money goes once deposited and are challenging the big banks.”

Savers can find out about the projects their deposits are funding via the website www.knowwhereyourmoneygoes.co.uk.