Seamus Twomey Seamus Twomey ( 5 November 1919 – 12 September 1989 ) was an Irish republican paramilitary and twice chief of staff of the Provisional IRA . Biography . Born in Belfast , Twomey lived at 6 Sevastopol Street in the Falls district . Known as " Thumper " owing to his short temper and habit of banging his fist on tables , he received little education and was a bookmaker ' s ( bookie ' s ) ' runner ' . He began his involvement with the Irish Republican Army in the 1930s and was interned in Northern Ireland during the 1940s . He opposed the leftwing shift of Cathal Goulding in the 1960s , and in 1968 , helped set up the breakaway Andersonstown Republican Club ( later the Roddy McCorley Society ) . In 1969 , he was prominent in the establishment of the Provisional IRA . By 1972 , he was Officer Commanding of the Provisional IRA Belfast Brigade when it launched its bomb campaign of the city , including Bloody Friday when nine people were killed . During the 1970s , the leadership of the Belfast Brigade of the IRA was largely in the hands of Twomey , Ivor Bell and Gerry Adams . In March 1973 , Twomey was first appointed IRA chief of staff after the arrest of Joe Cahill . He remained in this position until his arrest in October 1973 by the Garda Síochána . Three weeks later , on 31 October 1973 , the IRA organised the helicopter escape of Twomey and his fellow IRA members J . B . O ' Hagan and Kevin Mallon , when a team hijacked and forced the pilot at gun - point to land the helicopter in the training yard of Mountjoy Prison . After his escape , he returned to his membership of IRA ' s Army Council . By June / July 1974 , Twomey was IRA chief of staff for a second time . He took part in the Feakle talks between the IRA and Protestant clergymen in December 1974 . In the IRA truce which followed in 1975 , Twomey was largely unsupportive and wanted to fight on in what he saw as " one big push to finish it once and for all " . IRA informer Sean O ' Callaghan claims that on 5 January 1976 , Twomey and Brian Keenan gave the go - ahead for the sectarian Kingsmill massacre , when 10 unarmed Ulster Protestant workmen were executed by the Provisional IRA in retaliation for the earlier loyalist paramilitary murders of five Irish Catholics in the same area . It was Keenan ' s view , O ' Callaghan claims , that " The only way to knock the nonsense out of the Prods is to be 10 times more savage " . Twomey was dedicated to terrorist paramilitarism as a means of incorporating Ulster into the Republic of Ireland , in an interview with French television on 11 July 1977 , he declared that although the IRA had waged a campaign for seven years at that point , it could fight on for another 70 against the British state in Ulster and in the rest of the United Kingdom . Twomey supported the bombing of civilian targets , which he justified on class - lines . On 29 October 1977 , for example , a no - warning bomb at an Italian restaurant in Mayfair killed one diner and wounded 17 others . Three more people were killed in similar blasts in Chelsea and Mayfair the following month . As Twomey explained : “ By hitting Mayfair restaurants , we were hitting the type of person that could bring pressure to bear on the British government ” . In December 1977 , he was captured in Sandycove , Dublin by the Garda Síochána , who had been tipped - off by Belgian police about a concealed arms shipment , to be delivered to a bogus company with an address in the area . They swooped on a house in Martello Terrace to discover Twomey outside in his car , wearing his trademark dark shades . After a high - speed pursuit , he was recaptured in the centre of Dublin . The Gardaí later found documents in his possession outlining proposals for the structural reorganisation of the IRA according to the cell system . Twomey ' s arrest ended his tenure as IRA chief of staff . In the 1986 IRA split over abstentionism , Twomey sided with the Adams leadership and remained with the Provisionals . After a long illness , Twomey died in Dublin in 1989 but was buried in the family plot in Milltown Cemetery , Belfast . His funeral was attended by about 2 , 000 people . As Twomey is listed on the IRA ' s roll of honour under the category " GHQ staff " , this suggests that he was a member of the IRA ' s leadership until his death .