Charities that "pester" donors by phone and email are putting people off donating to the tune of £1bn a year, according to a survey by a market research agency.

Some £10bn is donated to charity every year in the UK. But according to the Beautiful Insights agency the figure could be "a lot more".

Beautiful Insights carried out a nationally representative survey of 1,017 UK-based adults over a four-day period in July. Just over one-third said they would not donate to charity in case they were "pestered" for more money at a later date.

People who were put off donating said they would have given an average of £5.86 a month - equating to £96m per month of lost earnings for UK-based charities.

Beautiful Insights said new regulatory proposals following the death of Olive Cooke could mean "charities across all sectors would have to totally rethink their fundraising approach" with "many fearing disastrous implications".

Fundraising activity prompts people to give

The survey also reveals that half the people who gave to charity did so as a direct result of fundraising activity.

But "with direct marketing channels being affected by the consent changes, charities face a dilemma", the agency said.

"The obvious switch to more broadcast advertising is an option but that will significantly increase overall costs," it said.

Some 14 per cent of regular donors said they would agree to a yearly automatic increase in donations. For donors giving an average of £5 a month, and increase to £6.50 over a three-year period equates to an additional £47m for the sector.

Paul Seabrook, managing director of Beautiful Insights said: "There’s been a negative spotlight on the charity sector recently. For some, the forecast is even gloomier with potential change on its way and the impact that this could have on donations.

“Removing certain barriers to giving such as the conveyer belt of additional requests for money that can often follow a donation could result in a significant uplift in support.  Charities need to differentiate between a spontaneous random act of kindness and a proactive donation driven by personal experience that could lead to someone giving significant support over many years.

“We’re a charitable nation. People want to give. If the technique is right, charities could see a significant uplift, with or without the consent changes."