GlaxoSmithKline, the Anglo- American pharmaceuticals group, has surprised its leading institutional investors by announcing groundbreaking plans to increase the pay awarded to non-executive directors.

Under the proposals, some of the company's leading non-execs will receive close to £100,000 a year.

The average basic pay for a non-exec of a top UK-listed company last year was £37,500.

The announcement - contained in a consultative letter to investors - would make many of GSK's non-execs among the highest paid anywhere in the world.

GSK has "benchmarked" the rise against a comparator group containing large UK-listed companies, a measure often used by companies to justify pay for senior full-time executives.

Non-executive pay has been increasing across the world to reflect the greater burden and reputational risk associated with directorships following recent corporate scandals in the US and Europe.

GSK non-execs are to collect a basic £60,000, a rise of 7 per cent.

Those non-execs who act as chairman of the remuneration or nomination committee will collect a further £20,000, twice as much as before, with the audit committee chairman taking an extra £30,000.

In another new feature, 25 per cent of the total pay awarded will be paid in GSK shares and only redeemed when the non-exec leaves the company.