 Complete the following phrase:  Some of the most indiscriminate bombing attacks and killings of the IRAs bombing campaign were carried out by a unit of eight IRA members, which included the Balcombe Street Gang, who were sent to London in early 1974. They avoided contact with the Irish community there in order to remain inconspicuous and aimed to carry out one attack a week. In addition to bombings, they carried out several assassination attempts. Ross McWhirter, a right wing politician who had offered a 50,000 reward for information leading to the arrest of the bombers, was shot dead at his home. The group later made an assassination attempt on Edward Heath. They were eventually arrested after a machine-gun attack on an exclusive restaurant on Mayfair. Pursued by police, they took two hostages a married couple and barricaded themselves for six days in a flat on Balcombe Street before they surrendered, an incident known as the Balcombe Street Siege. They were sentenced to thirty years each for a total of six murders. At their trial, the group admitted responsibility for the 