Prime Minister David Cameron has expressed his deepest sympathies for the families of those killed in the Chevron blast last week.

In response to a question from local MP Simon Hart, Mr Cameron called it a "tragic incident" and paid tribute to the local community.

Mr Hart asked Mr Cameron at today's Prime Minister's Questions if he would endorse the safety record of Chevron and its new owner Valero in what can be a dangerous industry.

"The company has had a good safety record, and in an industry in which there are inherent risks," agreed Mr Cameron. He said he believed that there would be lessons to be learned from the incident and added that he would be happy to discuss the issue with Mr Hart.

Four contractors died in last week's blast: Julie Jones, 54, of Pembroke, and Dennis Riley, 52, Robert Broome, 48, and Andrew Jenkins, 33, all of Milford Haven.