Susan Tollefsen will become one of Britain's oldest mothers when she gives birth by caesarean section next week.

The special needs teacher from Romford, east London, was sent to hospital for emergency tests after an examination by her GP revealed a "hard abdominal mass".

Ms Tollefsen feared the worst, but was instead congratulated by the sonographer at Nuffield Hospital, Essex, who told her she was almost 30 weeks pregnant.

She said she was "very excited" about the "miracle baby" she has already named Freya.

The shock pregnancy follows several years of IVF treatment for Ms Tollefsen and her partner Nick Mayer, 46, a warehouse manager.

She said Mr Mayer had been stunned by the news.

"First he was stunned and then he burst into tears. He was thrilled. It was the very last thing we'd both been expecting," she said.

The couple believed their chances of conceiving a baby through IVF were over when Ms Tollefsen appeared to suffer a miscarriage within four weeks of two fertilised embryos being implanted at a Russian fertility clinic.

A blood test and home pregnancy test both came up negative. She now believes she miscarried one twin, and that the other survived.

All scans have so far shown the baby to be developing normally, Ms Tollefsen added.

"I just feel incredibly excited. I know that when Freya is ten I'll be 67 and I do wonder how she will feel about that, but we'll have to cross that bridge when we come to it. Besides, I think there are advantages to being an older mother. You are more patient, wiser, and having worked with them all my life, I have experience of children which means motherhood won't come as such a shock."