More than one in 20 women who gave birth in Sutton and Merton recently smoked through their pregnancy, risking serious health problems for their child, new figures show.

They reveal 6.3 per cent of women giving birth in the area in the final three months of 2011 described themselves as smokers when their baby was delivered.

The figure was based on a study of 1,419 mothers in the two boroughs.

It is higher than the London average of 6.1 per cent - but less than half the English average of 13.4 per cent, and lower than last year's figure of 7 per cent.

The country's highest rate was among mothers in Blackpool, where the figure was 30.3 per cent smoked through their pregnancy. The London boroughs of Brent and Westminster had the lowest figures, of 2.8 per cent.

The statistics were published by the NHS Information Centre.

Chief executive Tim Straughan said: "Smoking can cause a range of serious health problems, including lower birthweight, pre-term birth, placental complications and perinatal mortality."