Little Courtney-Leigh Davies was happily playing outside her home on Elizabeth Street in Blackpool when the surface is said to have crumbled underneath her.

She suffered a bump to the head and has been limping since falling down the hole.

Courtney-Leigh's father, David Davies, said: "Courtney was just playing about. The ground just fell from under her feet and she fell down the hole.

"She screamed her head off so we took her to the walk-in centre. She keeps rubbing her head and she's got a limp.

"We've been through enough this year. We lost our son, Mckenzie – he was stillborn. We don't want anything to happen to Courtney-Leigh, we cherish her."

The incident happened after Mr Davies' neighbour, Michael Adams, complained to United Utilities that he could not find the stopcock for his house which had been covered over when the alleyway was transformed into a play alley in May.

United Utilities contracted Balfour Beatty construction company to dig up a section of the play area to find the stopcock two weeks ago.

When they failed to find it workmen filled the hole back up to surface level.

But Mr Adams, 38, of Elizabeth Street, claims the workers did not cover the hole properly.

He said: "They filled it back in but there was no board to cover it over, it was still wide open. It's supposed to be a safe area for kids. It's disgraceful."

And Mr Davies, 24, says more should have been done to make the area safe for his daughter.

He said: "There were no barriers. When she fell down the hole she was in the ground up above her knee cap."

A United Utilities spokesman said workmen returned to the site on Monday to try to find the stop cock again.

He said: "We used mapping and records to find exactly where it was and workmen returned to the site to dig another hole.

"We are quite concerned that a member of the public is reporting an incident where they fell because we have not left a site safe.

"We will be carrying out inquiries."

A spokeswoman for Blackpool Council said: "The company we contracted for the play alley covered up the stopcock.

"United Utilities have had to carry out work to resolve the problem.

"We will speak to the contractors to ensure the problem does not arise in the future."