The Bexleyheath Academy schoolgirl, who allegedly had an affair with an assistant vice principal, "undoubtedly lied", a court has heard.

Married father-of-one Stuart Kerner, from Aylesford, is accused of six counts of sexual activity with a child and two counts of sexual activity with a child by a person in trust.

The relationship allegedly took place between March 2011 and November 2012.

The girl, who cannot be named for legal reasons, was 15 and 16 years old at the time.

Defence counsel Edward Ellis told Inner London Crown Court: "The defence case is that (the girl) was a person who undoubtedly lied.

"He (Kerner) was a man who didn't look behind his back. He was stalked and information was found out about him for this carefully constructed elaborate rouse.

"We already know about Mr Kerner. He is man of good character, he has had no involvement with the police before, this is his first time being interviewed.

"Without a shadow of a doubt Mr Kerner cooperated, cooperated, cooperated (with the police).

"He has nothing to hide, nothing at all.

"All the teachers on the prosecution have said what a great teacher he was.

"It is not very pleasant to talk about (the girl) as a liar, but it is a very important part of this case. You have to believe one part or the other."

The court was told the girl once lied that she had been involved in a road accident, keeping up the pretence for months so she could get out of PE.

Kerner, giving evidence, talked of how he would use a school library as his office, which is where the girl would also spend time.

He said: "At lunch times I'd be trying to work and she'd be flitting around.

"She'd try to make me a cup of tea, or make conversation about things.

"There were times when I had to say 'go somewhere else I have got a deadline to meet'."

He added he would talk to the girl, but his relationship with her was no different to that which he had with other students at the school.

Talking of his relationship with students in general, he said: "I have always treated young people at school as people. I have always treated them with respect.

"I have always had a very good relationship with students, more so than other colleagues who saw them as, perhaps, more of a chore.

"A student once told me as I walked down the corridor: 'you're weird sir'.

"I said: 'why?'

"He said: 'because you smiled at me'.

"I couldn't go from one end of the corridor to the other without kids engaging me in conversation and talking to me."

Kerner added he was a very open person and information the girl knew about him and his home life - including the fact he had a scar on his back from having a mole removed - could have come from overhearing conversations.

The court has previously heard she also had access to photos on his iPad, which the defence claims is how she knew the lay out of his house.

The court heard Kerner, a religious education, ethics and politics teacher, was an alter server at his local church in Kennington from the age of 15, before doing a degree in Divinity and Theology at King's College London, where he met his wife.

At one point he considered becoming ordained, but instead took a PGCE and became a teacher.

He started working at Bexleyheath Academy, then known as Bexleyheath School, in 1999.

Kerner denies all charges.

The trial continues.