The announcement follows the result of the transfer of engagements ballot staged by the GPMU in August, which saw an overwhelming 86% majority of GPMU members vote in favour of the proposals to merge.

Print will now have a greater representation at union level, with the GPMU becoming one of the largest sectors - Graphic and Media - within Amicus.

Some 20,000 Amicus members will be added to the new sector's membership, which will encompass 170,000 GPMU members.

Amicus is the UK's largest manufacturing, technical and skilled persons' union, with over 1.2m members within the private and public sectors.

GPMU general secretary Tony Dubbins will become a deputy general secretary of Amicus, under its general secretary, Derek Simpson.

GPMU deputy general secretary Tony Burke will become an assistant general secretary.

Simpson said Amicus would enhance its political and industrial influence through the increase in membership and diversity gained by the GPMU merger.

"Our collective strength will enable us to be an even more powerful voice for our members concerns and aspirations," he said.

Dubbins said the confirmation of the merger was great news for GPMU members, and a progressive development for both Amicus and the trade union movement as a whole.

In due course the GPMU's headquarters at Bedford will close, with staff relocating to Amicus offices in either Covent Garden or Bromley.

The sectors within Amicus include aerospace and shipbuilding; construction and contracting; education; finance; and food, drink and tobacco among others.

The merger with the GPMU follows soon after Amicus' merger with finance sector union UNIFI, whose 150,000 members it joined forces with in August this year.

Story by Andy Scott