MP Marie Rimmer, 69, denies kicking Patricia McLeish and acting in a threatening or abusive manner towards her and fellow independence campaigner Dennis Ashcroft.
Giving evidence at Glasgow Sheriff Court, Mr Ascroft, 53, said the Labour MP pointed in his face and told him to “keep your mouth shut” as they campaigned outside Shettleston community centre in Glasgow at about 11am on September 18 2014.
Mr Ashcroft told the court on Tuesday there had been a discussion about how closely his car - decorated with Yes stickers - was parked to the polling station but said there was “no trigger” for Rimmer’s alleged actions.
He said: “She was pointing in my face. Right up to my face. I heard her say something like ‘I don’t like you, don’t speak to me, keep your mouth shut’, something like that.”
Under cross-examination, the St Helens South and Whiston MP’s solicitor Liam Ewing said Mr Ashcroft had tried to intimidate his client.
Mr Ewing said: “You pointed to a car and said ‘the one before you is tied up in the back’.”
Mr Ascroft denied that and said: “No. That never happened.”
Mr Ewing also said the witness had interrupted Rimmer when she was talking to two voters about Gordon Brown.
The solicitor said: “It was at that point Ms Rimmer said you were out of order.” Mr Ashcroft said: “No, that’s a lie.”
The trial in front of Sheriff Kenneth Hogg started in April but has faced a number of adjournments.
Mr Ewing also questioned how Mr Ashcroft came to be involved in the case.
Mr Ashcroft said he had come to the court for an earlier intermediate hearing to watch proceedings before he was called as a witness in the case.
The witness said “maybe it was on Twitter or something” when asked how he knew about the case but later revealed he had met the mother of Ms McLeish at a shop and found out about the assault case.
Mr Ashcroft was later contacted by police and gave a statement on September 2 2015 but denied he had discussed the case with any witnesses.