Senior Constable Gregory Betham was working for DPS at the time, and is the officer who eventually escorted Boyd outside the restaurant.
He told the court that Boyd approached the Prime Minister's table twice to ask for a photo, and they were concerned by his behaviour.
"We moved after Mr Boyd came over to talk to us the first time.
"We had enough concerns that we shifted tables to one next to the Prime Minister, which we had reserved as well."
Betham told the court that as Boyd was leaving the restaurant it became clear the situation was escalating.
"We could hear him say – it was more than talking, because we were quite a way down, at least half way down the restaurant. We were able to hear him from there.
"He was pointing, and I could clearly hear him talking about the Prime Minister.
"When I went down to see what was going on, it was becoming quite heated. Even if I'd been acting in a normal uniform role, the best thing is to get the parties outside.
"Especially the way Mr Boyd was gesticulating and starting to yell, by that stage."
Betham told the court he removed Boyd without force, leading him outside by the arm, and releasing him once they were around the corner.
Boyd claims his arrest was unjustified, as DPS officers should have checked with Key whether he was happy to pay for the meal.
He said that when he asked Key to pay for his dinner, the Prime Minister responded by saying 'absolutely'.
Key denied that at the time and also in a sworn statement to the court. He said he responded with 'yeah lots of people say that'.
When leaving the restaurant, Boyd told Green Parrot staff that Key's table would be paying his bill.
Boyd's lawyer Douglas Ewen said police didn't properly investigate the situation before making the arrest.
"She [arresting officer Constable Eliza Beaumont] didn't even go inside to determine if the bill had been paid yet or not, or was this a dispute about something else.
"Was this simply a disorderly conduct?
"There's no evidence of any information interchange between Constable Betham and herself."
Ewen said police hadn't provided the evidence to show the arrest was justified.
Following the incident, police charged Boyd with theft for the meal he had eaten. A charge of breach of bail was added later, as officers suspected Boyd had breached his bail conditions by drinking alcohol.
Police withdrew the charges some days later.
Boyd is bringing his cases under a mix of common law and Bill of Rights claims, saying that he shouldn't have been arrested, and that the force used to arrest him was excessive.
He is bringing a further charge of excessive force being used to arrest him, in relation to a 2010 incident. Boyd was bitten by a police dog in the Botanic Gardens, while being sought for arrest in relation to a domestic assault.
Boyd is claiming $10,000 for assault and detention for the incident at the Green Parrot, $10,000 for being arrested for breaching bail conditions without reasonable basis, and $10,000 for damages for the dog bite.
The judge has reserved his decision, and warned that a verdict may not be possible before the Christmas break.
