British road race champion finished 10th in Welwyn Garden City today despite late bike change.

Lizzie Armitstead admitted her chances of taking the overall victory in the inaugural Friends Life Women’s Tour are all but overall after suffering another ill-timed mechanical problem today.

Armistead punctured at the bottom of stage four’s final climb of Digswell Hill with two-and-a-half kilometres of the stage remaining.

She changed bike and managed to rejoin the peloton, but as she finished outside of the top positions she missed out on crucial bonus seconds.

Stage winner Marianne Vos now leads Armitstead (Boels-Dolmans), who also finished yesterday’s stage into Clacton-on-Sea with a flat tyre, by 30 seconds.

“I felt good the whole way but it’s impossible to say what I could have done,” said the 25-year-old.

“I punctured at the bottom of the last climb; I changed bike actually because it was faster.

“I sprinted a bit crazily down the hill and managed to get almost to the front just before the last corner. I tried to dive-bomb the last corner, it didn’t quite work out. I had to stick the brakes on.

“It’s pretty annoying. there’s not much more to say. We had the whole classics season without any punctures. These things happen.”

When asked if Vos’s lead of half a minute over her – and 19 seconds to nearest rider Emma Johansson – was unassailable, Armitstead added: “I would say so, yes. Unless bad luck turns to good luck for us tomorrow. There are no mountains or anything to split it.”

However, she is likely to win one jersey in the race: that of the Leukaemia & Lymphoma Research Best British Rider, a classification she has led since stage two.