Almost three in four babies in Blackpool are born outside marriage or a civil partnership.
Figures from the the Office for National Statistics (ONS) show Blackpool has the third highest rate at 72.2 per cent; Knowsley is the highest at 74.8 per cent.
Harrow in London has the lowest rate in the country, with roughly one in five born outside marriage. The average for the whole of the UK is 48 per cent.
Separate figures on teenage pregnancies show that Barrow-in-Furness in Cumbria has the highest rate in the UK, with roughly 17 in every 1,000 girls under 18 giving birth last year.
Wokingham in Berkshire and Epping Forest in Essex have the joint lowest rate of just over one in 1,000.