Parliament is to vote on giving Information Commissioner Richard Thomas a 40 per cent pay rise, in a move intended to underline the increased importance and status of his post in the wake of mounting public concern over the security of personal data.

A motion is to be proposed by justice secretary Jack Straw on 24 November increasing Thomas's salary from £98,000 to £140,000, backdated to last November. The motion can be debated for up to one and a half hours in the Commons, and is unlikely to be seriously opposed.

Officials were keen to stress that the move is designed to reflect a sea change in the attitude of Whitehall towards the enforcement of data protection and freedom of information legislation.

It is also a recognition that the size of the Information Commissioner's Office (ICO) has increased by nearly 25 per cent and now approaches 350 staff.

The change requires Commons approval because the post is independent. Thomas is responsible to Parliament, not to the government of the day.

Thomas is understood to have demanded this recognition of his position when he agreed to continue in the post a year ago.

The ICO has since acquired the right to conduct spot checks of government departments and other public bodies to ensure compliance with data protection rules in the wake of a series of scandals.

The government is keen to strengthen the public standing of the ICO ahead of the introduction of identity cards, after being stung by Tory and Liberal Democrat warnings that bureaucrats incapable of securing personal data should not be trusted with a database containing the personal details of everyone in the country.

Thomas is to be replaced in June 2009.