Plans to create a "super union" with two million members has suffered a setback when the GMB withdrew.
Mr Woodley's T&G is still expected to merge with Amicus
The T&G and Amicus said last year they hoped to amalgamate - a plan now overwhelmingly rejected by GMB members.
It is thought the decision at the union conference in Blackpool was partly motivated by fears that the GMB's regional structure would suffer.
The T&G and Amicus said they would go ahead with a merger and expressed disappointment at the GMB's decision.
"The T&G and Amicus will now proceed with our planned creation of a new union to meet the great challenges facing people in the 21st century, a democratic and campaigning union which will fight back for employees in the workplace, will take trade unionism out to the millions of unorganised workers, will stand up for equality for all," they said in a joint statement.
"Such a union will, we believe, rapidly become attractive to other unions in this country and will build ever stronger links with trade unions around the world."
When they do merge the two unions will be able to boast a membership of around 1.9 million members making it one of the biggest labour organisations in the UK.
The T&G and Amicus stressed they respected the decision of GMB delegates.