The former Wigan and New Zealand captain took over last April but has been unable to repeat his old successes with the club and last Sunday's 63-4 home defeat by Hull KR put his job in jeopardy.
"We have decided to terminate Graeme's appointment," said Tony Chambers, the Widnes chairman. "We are sorry to do that because we know how much hard work he has put in, but in the end a judgement has to be made on results and the defeat by Hull KR was the last straw."
Colin Whitfield, the Alliance team coach, will take over for tonight's game at Hunslet and stay in charge for the rest of the season. Widnes say they have an open mind on West's permanent successor.
"We are ambitious to progress as a club and get into Super League," Chambers said. "Lack of finance this year has been a handicap, but we were still expecting to have done better with the team we've got."
Widnes are currently ninth of 11 teams in the First Division, a heavy fall from the early 90s when they were still capable of competing for the game's major honours. West, previously in charge at Wigan, is now being linked with Leigh.
London Broncos go into one of their biggest games of the season tonight disappointed in their failure to strengthen their pack for next term.
Tony Mestrov, now with tonight's opponents Wigan, has told London that he will not be returning to them next year, having accepted a new contract that will keep him at Wigan until 2000 instead.
London do introduce a new forward for a match that could be critical to their chances of forcing their way into the top five. Bart Williams, a former Australian Schoolboys hooker, has impressed playing for West London in the Rugby League Conference and wins a first chance at the expense of Robbie Beazley.
Martin Offiah is still not recovered from an ankle injury, but London will have Rob Smyth and Shaun Edwards, two former Wigan players, on duty.
They are hoping for better support than they have been getting so far at The Stoop this season and the signs are they will get it. Advance sales have exceeded the rate for the game against Canberra last year, which eventually drew 9,000, and the combination of good weather and the Broncos' improved form should give the gate a boost.
The Super League leaders make one change from the side that beat Halifax last week, Neil Cowie coming back from a hamstring injury at prop in place of Terry O'Connor.