John Green and Terence McCrory, Ulster Protestant hitmen recruited by drugs dealers in south London, had allegedly waited for Norris, 49, at his home in Belvedere, Kent.
Timothy Langdale, for the prosecution, said that Norris attempted to flee, but Mr Green shot him. He said that despite Norris's pleas for his life and offers of money, Mr Green then fired several more shots from a .25 calibre pistol into his victim.
Mr Green, 32, of Falkirk, Scotland, and Mr McCrory, 30, of Belfast, are on trial alongside Patrick Doherty, 35, of Brockley, south London, and George McMahon, 46, of New Cross, south London. Mr Green, Mr McCrory and Mr Doherty are charged with conspiring with others to kill Norris; all four are charged with conspiring with others to kill John Dale, a drugs dealer, while Mr Doherty and Mr McMahon are charged with conspiracy to supply cannabis resin. They deny all the charges.
The hitmen were hired, the Crown alleges, through drug dealers from Ulster who were promised access to cheap cannabis in return for fulfilling the contracts on Dale and Norris.
The Crown claims that Mr Doherty put the price of pounds 35,000 on Norris's head because he had 'grassed up a number of firms that year'. Mr Langdale said he told Stuart Warne, a go-between, that there were 'other hits in the pipeline'.
Mr Warne was told by Patrick McCreery, an Ulster dealer based in Kent, that to fulfil the contract on Dale - said to have 'ripped off' another dealer - the hitmen would require pounds 10,000 on top of the pounds 16,000 they were already being paid, to cover hotels, guns, motorcycles and cars. Mr Langdale said: 'McCreery struck Warne as a being a professsional. He indicated that the men could not use their own equipment because it would show it was an Irish job.'
Mr Langdale said Mr Warne met a man in a public house in south-east London and was taken to an estate where he bought a double-barrelled shotgun and cartridges for pounds 300.
Several attempts to kill Mr Dale failed, Mr Langdale said, and a shotgun attack was eventually carried out by another Ulsterman, Renwick Dennison, but the victim survived. The case continues today.