In future, pupils at Uplands Manor Primary School in Smethwick, West Midlands, will see their mistakes struck through with a green pen.

Critics have condemned the change as "politically correct" and "trendy".

But Penny Penn-Howard, head of school improvement for Sandwell Council, said: "The colour of the pen used for marking is not greatly significant except that the red pen has negative connotations and can be seen as a negative approach to improving pupils' work.

"Therefore, it is quite legitimate for a school to have a consistent policy that it uses a different colour."

Children not gullible

The red pen goes further back than most schools, having been developed during the mid-19th Century, when ammonia-based dyes became available.

The school took the decision to introduce green ink independently of the local authority.

Frank Betteridge, Conservative education spokesman on Sandwell Council, said: "Ever since people have written in coloured ink, blue has meant credit and red has meant debit.

"Children are not gullible. They will soon realise that green means the same as red used to.

"If it's a question in maths or spelling, it's either right or wrong. That needs to be emphasised.

"The remarks on the page should tell children where they are going right or wrong."

Uplands Manor, which has 630 pupils, denied green ink had been introduced to prevent hurt feelings.

But Nick Seaton, chairman of the Campaign for Real Education, said: "If you use red ink, pupils can see straight away where they have gone wrong and where they can do better.

"Children have to learn to take life's ups and downs. Banning red ink is a rather trendy and politically correct idea."