A second young girl has alerted police after noticing a mirror being placed under her changing room cubicle.

Hertfordshire Constabulary, said a 10-year-old girl reported the incident, which took place at the William Penn Leisure Centre in Mill End, on Tuesday, February 24, at 4.40pm.

A similar incident occurred at the centre between 6.45pm and 7.10pm on Tuesday, January 13.

PC Christian Gottmann, who is investigating, said: "These incidents will understandably be of some concern to the community but I would like to reassure people that we are doing all we can to trace the person responsible as a matter of urgency.

"I am appealing to anyone who was using the changing rooms at the times stated and saw anyone acting suspiciously, or loitering around, to contact me as soon as possible. I would also like to hear from anyone who may have noticed something similar happen but hasn't yet contacted police.

"If you do see anyone acting suspiciously, please inform leisure centre staff immediately."

Anyone with information should call 101 or Crimestoppers anonymously on 0800 555 111.