Cherie Blair is so concerned about the poor quality of school dinners that she may give her son Leo packed lunches, she revealed during a visit to Birmingham yesterday.

The Prime Minister's wife said she was worried about the quality of the food served to her fouryearold son, as she met parents and teachers in Edgbaston.

At the same time, at a press conference a few miles away at the International Convention Centre and flanked by senior Ministers, Leo's father was explaining how Labour would improve school dinners.

Tony Blair highlighted plans to provide an extra #210 million, after celebrity chef Jamie Oliver exposed the shocking state of school dinners in a television series.

But Conservative critics said Mrs Blair's comments proved the Government had waited too long to act. Mr Blair and his wife were in the city for an electioneering visit, as part of Labour's campaign strategy focusing on the regions.

Major election events have traditionally been held in London, but yesterday the Labour leader conducted a press conference in central Birmingham, alongside Culture Secretary Tessa Jowell, Labour's Children Minister Margaret Hodge and Health Minister Melanie Johnson.

Mrs Blair was visiting World's End Junior School in Quinton, in the key marginal seat of Edgbaston, accompanied by Labour candidate Gisela Stuart.

She said she was impressed by a tour of the school kitchens, where staff were preparing broccoli and Brussel sprouts.

But the food was less healthy at Leo's school in Westminster, she warned. Mrs Blair said: "They are not terrific, to be honest. I am seriously thinking about sending him in with a packed lunch."

The comments were seized on by Deidre Alden, the Conservative candidate for Edgbaston.

She said: "Cherie Blair has a line right to the top, so it's a pity she didn't use it if she was worried about the state of school dinners."

But Gisela Stuart said: "Schools in Birmingham have good kitchen facilities, so we can build on that.

"World's End is an example of a school getting it right, which I think is what prompted Mrs Blair's comments. I was a bit surprised by her honesty."

As well as the kitchens, Mrs Blair visited the school's breakfast club, where about 50 children enjoy toast and cereal before lessons each morning. She also saw the school's computer equipment and interactive whiteboards, which have replaced blackboards in classrooms.

Leo's primary school and Westminster local education authority declined to comment on Mrs Blair's remarks.

Ministers have vowed that at least 50p will be spent on ingredients for each primary school lunch and 60p in secondary schools.

A new School Food Trust will also be set up to advise on nutritional issues.

Schools will be encouraged to remove vending machines selling junk food, and a new advertising code of conduct will be drawn up to monitor advertisements on children's television.

Edgbaston is a former Tory stronghold, won by Mrs Stuart for Labour in 1997. It is a seat the Conservatives must win to form a Government. The Labour majority is 4,698.