The Stretch (Stephen Leather Thrillers)

As a big player in the 90s London underworld, Terry Greene has always made a priority of 'taking care of business' personally. It's always good for the troops to know that the boss ain't too squeamish to clean up his own mess. Preston Snow was out of line. So the up-close-and-personal visit was in no way out of character.
It was a messy hit. But the job was done.
More messy however, was the aftermath. Fingered by one of his own crew, Terry finds himself taking the fall and is put away for life. The only person he can really trust in the entire world is his estranged wife, Sam. She must now take over the reins of his organisation, find the snitch and - in theory - get Terry off the hook.