Members of the Welsh assembly are to receive a pay increase of 9.2 per cent following an error by the salaries board, it was revealed on Thursday.

The Senior Salaries Review Board set wages for assembly members at 73.3 per cent of that of an MP, instead of 74.3 per cent. Members will not receive backdated pay, but will receive an extra £500 this year, and a similar increase each year for the next two years.

Of the rest of the increase, £1500 was awarded last year but will be received now.

A backbencher salary will now increase from £38,000 to £41,500 per year. As first minister, Rhodri Morgan will be entitled to a further £69,862, an increase of 2.5 per cent.

A further £36,241 will be available to the presiding officer, ministers and Ieuan Wyn Jones, leader of the opposition, on top of their backbench wages.

Deputy presiding officer, John Marek, said: "We are dealing with public money and should be accountable. Of course it is invidious to set our own salaries and we need to do this as little as possible."

Welsh Conservatives have described the increase as "bizarre", while union leaders have condemned the move.

Gethin Lewis, Cymru secretary of the national union of teachers, said: "At a time when public service workers are only having inflationary or slightly above inflationary pay rises, this move by assembly members will be seen as crass and insensitive.

"Teachers in Wales will be shocked to hear that AMs will receive increases of over nine per cent while the teaching profession will only receive an increase of 3.5 per cent," he said.