Singer Kate Bush was forced to leave the stage and delay her concert in London for around 30 minutes on Wednesday night (03Sep14) after technical problems halted her performance.

The Wuthering Heights hitmaker was singing for 3,500 fans as part of her run of comeback concerts at the city's Hammersmith Apollo when a mystery issue caused her to head offstage.

A witness at the venue tells Wenn the unscheduled second interval lasted for more than 20 minutes before Bush returned to the stage to complete her performance. The concert ended 30 minutes after its planned finish time of 11pm.

Further details of the reason for the delay were not available.