Avanti West Coast strikes called off as RMT accepts rest day working deal / Mick Lynch announces retirement as head of RMT / RMT union boss Mick Lynch announces retirement / Mick Lynch to retire as RMT chief after nearly four years / RMT claims 'substantial victory' after tube pay dispute / Planned London Underground strikes by RMT workers suspended / Rail strikes threat averted as RMT workers accept pay deal / RMT union backs ex-Labour socialist mayor who criticised Keir Starmer / RMT backs independent candidate Jamie Driscoll for north-east mayor / RMT leader Mick Lynch gives Jeremy Corbyn general election backing