BRITAIN'S worst mum Karen Matthews was spotted shopping in Mothercare — as daughter Shannon celebrates her 20th birthday today.

Matthews, 43, was seen trawling through toys and baby-grows in a town in the south of England, where she relocated after her prison release.

The mum-of-seven was jailed for eight years in 2008 after staging the abduction of her daughter in a case that shocked the nation.

Shannon, then aged nine, was drugged and hidden under a bed as heartless Karen planned to cash in on reward money for finding her.

Matthews now goes under a new identity and was spotted shopping alone last week.

She wore a checked shirt and sunglasses while clutching a carrier bag and a SuperDry satchel.

Later she was seen scoffing on a McDonalds on a public bench after shopping in Poundland.

Matthews was found guilty of kidnap, false imprisonment and perverting the course of justice after her sickening abduction plot unravelled.

Innocent Shannon — who turns 20 today — vanished from their home in Dewsbury Moor, West Yorks.

It sparked a month-long police hunt while hundreds of volunteers poured into the area in a desperate bid to find the girl.

Matthews was seen shamelessly making public appeals for information on her daughter's whereabouts - despite knowing where she was all along.

Police discovered the child drugged and tethered in the base of a bed in nearby Batley Kerr.

She was at the flat belonging to Michael Donovan — the uncle of Karen's then-boyfriend Craig Meehan, who had nothing do with the snatch.

Matthews and Donovan devised the elaborate plot in a bid to claim the £50,000 reward money for finding Shannon.

Donovan was also jailed as Matthews' accomplice.

But callous mum Matthews insists she had nothing to do with the kidnap plot.

She said in May: "From the start I didn’t know where she was. Others were involved. I didn’t have a clue.

"You can’t kidnap your own child. I know the truth and I wasn’t involved in it. I still have nightmares thinking that it’s all going to happen again."