Reports are also appearing in sectors not traditionally targeted by campaigners, such as media and telecommunications.

“Corporate social responsibility reporting in the UK is reaching critical mass,” said Simon Propper, managing director of Context, the CSR consultancy that carried out the Directions study with SalterBaxter, a corporate identity and communications firm. “In most sectors, it’s only a small minority who don’t report. Unless you’re a maverick, this is an uncomfortable place for any company to be.”

However Nigel Salter, of SalterBaxter, said some reports reflected genuine CSR efforts while others could be merely “a fine coat of worthy gloss paint”.

This is underlined by a survey showing that, despite the emphasis on CSR, 74 per cent of employees believe they do not have enough opportunities to get involved with charities at work.

The survey, carried out by Shelter, the homelessness charity, to promote its Strip 4 Shelter campaign, found 47 per cent of employees unsure which charities their employers supported.

“This research clearly shows that what is happening at management level is not always communicated to employees,” said Peter Lambert, of Business in the Community.

The Directions study showed that 84 FTSE 100 companies now produce reports, with 11 reporting for the first time this year, including BOC, British Land and mmO2. Non-reporters include Associated British Foods, Daily Mail & General Trust, and Hays.

Laggard sectors were leisure and hotels, where only three of 17 companies report, and software and computer services, where no companies report. The Companies Act is expected to require disclosure by large companies on environmental and social issues.

The study also analysed leading US and European companies, finding that 22 of the S&P top 50 and 40 of the top 50 European companies produce reports.