Some of Britain's largest charities have been fined thousands of pounds by the Information Commissioner's Office after hiring private companies to snoop on their donors' wealth.

The ICO said that millions of donors had had their information misused by eleven charities who broke data protection laws while pushing for donations.

The charities, which include Great Ormond Street Hospital Children's Charity, the Royal British Legion, the NSPCC and Oxfam, were fined between £6,000 and £18,000 for hiring companies to collect information about donors without their knowledge.

The privacy watchdog said that some of the charities had been collecting information about donors including their income, property values and friendship circles.

Charities including Cancer Research UK, Great Ormond Street Hospital Children’s Charity, Macmillan Cancer Support, The Guide Dogs for the Blind Association, The Royal British Legion, and the NSPCC had been illegally screening their supporters based on their wealth, the ICO said.

This information was used to target the wealthiest donors, in particular to persuade them to leave the charity a legacy in their will.

Four of the charities were also fined for sharing information between themselves without donors' permission. The ICO said that some of them "don’t know if the information has been shared one or one hundred times".