A teenage motorist caused the death of a lifelong friend when his car crashed into a field after he tried an unsafe overtaking manoeuvre.

Aaron Murphy was detained for 20 months on Tuesday at the High Court in Edinburgh after pleading guilty to causing death by dangerous driving in the Borders.

The 19-year-old former schoolmate Dale Whillans was the front seat passenger in his Seat Ibiza which mounted a verge and hit a sign on the A698 Hawick to Jedburgh road.

Lady Wolffe told Murphy, of Braid Road, Hawick: "This is a sad and tragic case for all concerned."

The judge said the accused was "deeply remorseful" but added: "I am satisfied there is no alternative to a custodial sentence."

Murphy was also banned from driving for six years having admitted driving at excessive speed and crossing on to the other side of the road when it was unsafe, which led to the collision on April 6 last year.

Advocate depute Keith O'Mahony told the court Murphy had performed an overtaking manoeuvre to pass several vehicles at a location where it was unsafe to do so.

The prosecutor said: "The accused and the deceased were well known to each other. They had the same group of friends and had been schoolmates at both primary and secondary school."

On the day of the incident they and others had decided to drive in two cars from Hawick to Berwick upon Tweed. After passing through the village of Denholm they caught up with a queue of four vehicles.

They reached the Timpendean straight but oncoming traffic initially ruled out overtaking. Once the last of the oncoming vehicles had passed the first of their cars pulled out to pass the traffic ahead with Murphy following in his Seat.

Mr O'Mahony said the noise of the vehicles accelerating caught the attention of witnesses and one thought they were travelling at more than 70mph.

He said: "Other witnesses confirm the accused was travelling in excess of the speed limit, with one witness describing his speed as 'ridiculous'."

The lead car managed to complete the overtaking manoeuvre but Murphy's vehicle had insufficient time.

A couple travelling with young children saw his car come over the crest of a hill towards them and managed to bring their Saab almost to a halt.

Murphy's car went off the road and collided with a road sign before hitting a dry stone wall and rolling into a ploughed field near Timpendean Cottages.

The advocate depute said: "The vehicle came to rest the right way up. The impact caused extensive damage to the entire vehicle."

Murphy and another passenger, Lee Sanderson, got out of the vehicle but 18-year-old Mr Whillans, of Longcroft Road, Hawick, was unconscious and remained in the front passenger seat.

An off-duty surgeon and paramedic tried to give aid to the victim and got him out of the vehicle.

He was taken to Borders General Hospital before being flown by helicopter to Edinburgh but did not survive his injuries.