‘Evidence’ means any material that helps prove one side’s case or the other’s – what witnesses say, pieces of paper with things written on them (commonly known as ‘documents’), computer files, records of text messages, photographs, CCTV footage, emails, monogrammed handkerchiefs dropped at the scene of the alleged sexual harassment, bloodstained blunt instruments (admittedly these are rare in employment tribunal proceedings) – etc. etc..

It’s a common mistake to think that what witnesses say doesn’t count as evidence: as in “It’s my word against his, but there’s no evidence.” If he says you did and you say you didn’t, that’s evidence on both sides: the tribunal will just have to decide who it finds more believable.