Two bombs exploded at the Mulberry Bush and the Tavern in the Town pubs in 1974, killing 21 people and injuring 182.The IRA was immediately blamed, but denied any involvement - a denial which was always treated with scepticism by the police.Six men - known as the Birmingham six - were jailed for the murders but had their convictions overturned in 1991, after 16 years in prison.On Monday relatives of those who died met with the Chief Constable of West Midlands Police.They were told a fresh inquiry will not be set up, following a review of evidence in the case.There were angry scenes outside the meeting as the families expressed their disappointment over the decision.Julie Hambleton, who lost her sister Maxine, said: "We knew that they were not going to reinvestigate it."What is extremely insulting and disappointing for us as a family is the fact that our own police force has no interest in going looking for the perpetrators of the biggest unsolved mass murder in England of the 20th Century."We have been treated with such contempt for so many years. We have come to the conclusion that this is the nadir of our justice system. How much lower can you go?"Chief Constable of West Midlands Police Chris Sims explained the decision by saying there had been "insufficient evidence" for proceedings."There have been questions over the years why certain individuals such as the people named by the media apparently never formed part of any investigation," he said."I want to be open and transparent today and tell you that these men had been subject to investigation in the 1970s and the 1991-94 investigation."There was insufficient evidence for proceedings against any person. My professional judgement is that the 1991 to 94 investigation was carried out to a good standard."The relatives of those killed say West Midlands Police refused to comment on whether anyone had received a so-called "on-the-run" letter in relation to the bombings because of the ongoing judicial investigation into the letters.They say they are determined to fight on to bring those responsible to justice.