Dave Chapple, who is the local representative of the Communication Workers Union (CWU), said the company has increasingly made it difficult for his colleague Andrew Mootoo, who has multiple sclerosis, to return to work.
He told Politics.co.uk: ‘When Andrew was first diagnosed 18 months ago, they tried to pay him off but had to back down after we [the CWU] pointed out it was illegal.
‘Since then they’ve come up with every excuse you can think of to stall his return to work.
‘What made this remarkable is that so many people walked out in solidarity with somebody they haven’t even seen for 18 months. I’ve also received around 200 emails of support from fellow trade unionists and disabled people.’
Royal Mail have reportedly told the strikers they will sit down with Andrew to find a solution.
Chapple added that this situation highlights the difficulties disabled people face in the workplace.
The strike comes after the government’s trade union bill had its third reading in the House of Commons.
A Royal Mail spokesperson apologised to customers for the disruption.