Mick Cash, the RMT's senior assistant general secretary, said Mr Crow's death had rocked the trade union movement, both in this country and around the world.
The thousands of messages of condolence from every part of the globe are a testament to the courage, leadership and strength that Bob shared with so many people.
Whilst Bob Crow's funeral itself will be a strictly private affair, his friends and family recognise that many people will want to show their solidarity, respect and support, both on the day itself and on May Day. These arrangements give everyone a chance to play their part.
More top news
A dramatic car chase has been spotted in central London amid filming for the next Transformers film.
Londoners have been stunned by a tattoo convention in which six body artists finished one person's back.
A map showing how Londoners are leaving capital has been drawn up from official statistics.