The Royal Parks, which are responsible for the upkeep of the memorial, said it would be shut for “as long as it takes” while work was carried out to replace grass around the granite oval and to install steel bars below bridges on the fountain to prevent children getting trapped.

It will be the second extended closure for the £3.6m fountain in Hyde Park, London, since it was opened by the Queen in July. Within days it was shut after three people slipped and injured themselves. There were also smaller closures caused by flooding and blocked water pumps.

The latest measures are being implemented after Royal Parks staff highlighted possible danger areas including the possibility of a child becoming trapped under the bridges that span the water channel.

Grass around the memorial will also be replaced. Although the Royal Parks say this is mainly for aesthetic reasons, they hope it will avoid the problems of last summer when heavy rain and high visitor numbers turned the ground around the fountain into a mud bath.

Although they have not decided a date for the closure, they would like the work to be carried out before the busy Christmas holidays when the memorial will attract many visitors. According to the Royal Parks, present visitor numbers at the fountain are as low as 180 on weekdays.

The Royal Parks disclosed that since the memorial opened in July, five people had been taken to hospital by ambulance. Three had leg injuries, one injured an arm and a fifth had a head injury after slipping on the fountain.

A spokesman said a further “several hundred” people had slipped over in and around the fountain but had not needed hospital attention.

After the initial accidents, steel fences fitted with gates were erected around the memorial and six safety stewards were employed, increasing the running costs by more than £100,000 a year.

The texture of the granite was roughened to improve grip underfoot and, under new guidelines, visitors could paddle their feet and dip their hands in the water but were no longer allowed to run or walk in the fountain.

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