A dad has spoken of his anger at the three-year sentence given to a "callous and ruthless" man who abused his two daughters in their own home.

The two sisters - now in their 30s - were repeatedly abused as young children by computer technician Colin Clark, 55, who used to work at Brunel University. He was jailed for three years on Tuesday.

The father of the two girls told the Hillingdon Times, sister paper of Local London: "I speak for the whole family when I say he got off light. Not only did he abuse the two girls, he abused the hospitality I offered to him and his family, in my house and under my roof.

"One thing you would think as a parent is that your children are safe in their own home."

He added: "He was callous and ruthless. The fact that he pleaded not guilty meant that the girls had to re-live their ordeal and go through all that pain again.

"Three years is what he has got. He will probably be out in 18 months, but my girls will carry the scars for the rest of their lives."

Clark, of Norwood Close, Southall, was found guilty by a jury on eight charges of indecent assault and one of indecency with a child relating to the girls when they were aged between seven and 14, and ten and 13.

Now both grown-up, one with children of her own, they told the trial at Isleworth Crown Court how Clark would constantly touch them when they were small - the older one by sitting her on his knee while reading to her and occasionally when she was in bed.

The younger girl complained of his "pushing her up against a wall and pressing himself to her", prosecutor Rosie Burns told the jury.

The assaults happened when the father-of-three visited the girls' family, sometimes on holiday in the west country.

When the girls finally told their mother, she did her best to "brush it under the carpet" because of the effect it would have on his family, said Ms Burns.

Clark was not arrested and questioned until March last year when he denied everything except two minor incidents with the younger girl which, he agreed, were "inappropriate".

He denied touching either of them in any sexual way.

Defending, Christopher Drew said he had already been punished to some extent, having been "sent to Coventry by his family".

"He does express remorse for the damage he has done. This is a tragedy and for that he feels remorse. He has had great difficulty accepting the jury's verdicts," he said.

Jailing Clark, Judge Hezlett Colgan told him: "The aggravating features of this case are clearly the ages of the girls at the time and your position of trust in relation to them.

"Both young women are still suffering the after effects of what you did to them."

Clark must sign onto the sex offenders' register for life and is banned from ever working with children.