The poor health of a man accused of murdering his three-year-old son and the child’s mother more than 40 years ago may prevent him from standing trial, a court has heard.

William MacDowell, 79, allegedly killed Christina ‘Renee’ MacRae 36, and her child Andrew, with the pair last seen driving out of Inverness on November 12 1976.

In June, his lawyer, Murray Macara QC, entered not guilty pleas to all charges on his behalf and lodged special defences of alibi and incrimination.

On Friday at the High Court in Paisley, Mr Macara said MacDowell, who was absent from court, is suffering from cardiac failure, liver failure, and lymphoma.

MacDowell, of Penrith, Cumbria, moved GPs in April and his current practice “did not feel confident about expressing an opinion about his fitness to stand trial”, Mr Macara told the court.

A medical expert has been instructed to look over MacDowell’s medical records over the next week to see if he is fit enough to be tried over the allegations, the defence lawyer said.

Judge Lord Armstrong said: “The first and most pressing issue clearly is the fitness of William MacDowell.

“We need to get the necessary information before any decision is made on other matters.”

He set a date of 9.30am on September 28 at the High Court in Glasgow for the next preliminary hearing in the case, which MacDowell was excused from attending in person.

Prosecutors allege that MacDowell assaulted his son and Ms MacRae at a lay-by on the A9 trunk road near Dalmagarry, or elsewhere, on November 12 1976 and that he caused them injury by unknown means, as a result of which they died, and murdered them.

He is also charged with attempting to defeat the ends of justice by disposing of the two bodies and their personal effects by means unknown to prosecutors.

Moreover, he is accused of disposing of a pushchair, setting fire to a BMW vehicle and disposing of a boot hatch from a Volvo vehicle to conceal the alleged crimes and avoid detection, arrest and prosecution.

He denies all the charges.