Two women were killed and one critically injured in the shooting

Vicky Horgan, 27, and sister, Emma Walton, 25, died on Sunday in Highmoor Cross, Oxfordshire. Their mother, Jacqueline, is still critically ill.

Stuart Horgan, 39, of no fixed address, is charged with two murders and one attempted murder.

The review will examine why it was more than an hour before medical teams were allowed onto the scene of the shooting.

Police say the delay was because they had to make the area safe.

A police spokesman said: "This comprehensive review will examine all aspects of the response and subsequent actions taken by the emergency services involved."