Mrs Pemberton and her son were also killed by her husband

Frank Mullane's sister Julia Pemberton and her son, Will, 16, were killed at their Berkshire home in November 2003.

He has now spoken out after the inquest into the deaths of Vicky Horgan and Emma Walton, who were shot dead at a family barbecue in Oxfordshire in 2004.

Mr Mullane, from Wilts, has called for changes to police firearms policies.

The 44-year-old attended Wednesday's inquest into the deaths of Ms Horgan and Ms Walton, sisters who were shot dead in Highmoor Cross by Ms Horgan's 39-year-old husband Stuart.

The sisters were shot dead by Mrs Horgan's husband

Horgan also shot at their mother Jacqueline Bailey. She criticised police delays in entering their house after the shooting. Her criticisms were echoed by Oxfordshire's coroner, Nicholas Gardiner.

Mr Mullane joined the criticisms, saying: "Thames Valley Police firearms' policy should have changed after my family's tragedy six-and-a-half months before this case.

"In this case, as in ours, there appear to have been errors alongside a bizarre and completely ineffective firearms policy.

"Thames Valley Police must be held accountable at the highest levels to ensure that promised changes are carried through so that police officers, many of whom are frustrated by that policy, can carry out their role to preserve and protect life."

A spokesman for the force said changes brought in since the tragedy meant it was "far more effective at dealing with spontaneous firearms incidents".

Mr Mullane also believes Thames Valley Police failed to take adequate steps to prevent the murders of his siter and nephew by Mrs Pemberton's abusive husband in Hermitage.