Rebecca Casterton and Lauren Brooks were on their way home

Robert Murray, of Telford, Shropshire, was jailed for causing the deaths of Rebecca Casterton, 13, and Lauren Brooks, 12, in Staffordshire in 2006.

The 51-year-old driver had finished a mobile call moments before the crash.

The family appeal comes a day after the government announced new laws for those caught using phones while driving.

Motorists now face being given three penalty points on their licence and fines of �60 for the offence.

In a statement, the girls' families said their deaths were "avoidable".

Our appeal is for people to... never use their telephones while driving Families' statement Driver jailed over girls' death

"A year ago two young lives were lost unnecessarily because the driver of a lorry was too busy using a mobile telephone to concentrate on the road and other road users," they said.

"Our families' lives will never be the same again and we have to live with this loss for the rest of our lives."

They said that every day the families had to watch "people holding and using their mobile phones while driving".

"Our appeal is for people to think long and hard of the potential life-changing consequences of their actions and never use their telephones while driving."

Murray, of Wrockwardine Wood, had denied the charge but was convicted following a trial at Stafford Crown Court in November.

Robert Murray had used his phone moments before the crash

Jailing him for four-and-a-half years on Tuesday, Judge Paul Glenn said he accepted Murray had not being making a call at the time of the accident but added he was satisfied his attention was diverted by the phone.

The two girls were being driven home from a horse riding lesson and were back-seat passengers in a Renault Clio.

They were travelling southbound on the A38 at Clay Mills, near Burton, on 20 January last year, when the collision took place.

Rebecca, from Barton-under-Needwood, died at the scene. Lauren, from Burton, was pronounced dead at hospital shortly afterwards.