Forty-one charities were in contact with the Charity Commission because of issues arising during this year’s general election campaign, the regulator has said.

In an overview of charities’ campaigning and political activity during the most recent election period, which ran from 18 April to 8 June, the commission said that 28 out of the 41 cases it dealt with arose from concerns raised by members of the public or the regulator proactively identifying concerns from media reports.

A further 13 charities contacted the commission to seek advice.

In comparison, 39 charities were in touch with the commission during the 2015 general election.

The majority of the charities the commission dealt with during the most recent election had incomes exceeding £1m a year, the regulator said, and the 41 cases included concerns relating to all the major political parties.

The Charity Commission’s guidance on political activity says that charities must stress their political independence and campaigning should be undertaken only in furtherance of a charity’s charitable purposes.

A number of charities also expressed concerns about the impact of the lobbying act on their ability to campaign during the most recent election, specifically its spending limits on joint campaigning and registration with the Electoral Commission.

Among the charities contacted by the regulator during the 2017 election was the right-wing think tank the Institute of Economic Affairs, in relation to allegedly partisan publications.

The IEA was issued with formal regulatory advice about two publications, one suggesting Conservative manifesto policy proposals and another criticising the Labour manifesto.

Another two cases highlighted by the commission in its report today is Unity Group Wales, which was displaying Labour Party posters in its high-street centre in Swansea, and the National Council of Hindu Temples, which issued an email to members suggesting support for the Conservative Party.

Unity Group Wales immediately removed the posters when contacted by the commission and made a statement expressing its political neutrality and independence.

The National Council of Hindu Temples initially denied its email was partisan and the commission said it considered an official warning until the charity decided to send a second email saying it was politically neutral.

David Holdsworth, chief operating officer of the Charity Commission, said: “Charities have a strong and proud tradition of campaigning and being at the forefront of social policy. Many charities can and did find practical, valid ways to engage in beneficiary-focused and effective campaigning and political activity in the run-up to this general election.

“However, our report does illustrate that some basic silly mistakes that could have been avoided by reading and following our guidance continue to be made by charities.”