Two runners will run three marathons in three days this month.

They'll also be wearing huge rubber boobs!

The Daveys are running to raise money for breast cancer research, as both their grandmothers died from the disease.

They designed the huge rubber boobs to attract donations in a lighthearted way.

Siblings Patrick, 30, and Kate, 25, will be running two courses they designed themselves, around Southampton and London.

Kate is based in Tooting Bec, while Patrick studies medicine in Southampton.

The finale is the Brighton Marathon on 16 April.

Mr Davey said: “Personally it means a great deal to us and I hope it will strike a cord with many others who have lost loved ones in the same way.”

They have been training since October, suffering bruises and aches and pains.

Mr Davey also said: “Physically, it has been an enormous challenge but really it is three days of pain for us which is nothing compared to what people suffering from this dreadful disease have to go through.”

The pair have a blog, http://boobrunners.wordpress.com/ and have started a facebook group.

They are also on the just giving website http://www.justgiving.com/twoofthebreast