An elderly British couple appeared in court this week, more than 40 years after they allegedly hired a killer to take out the husband's previous wife.

Prosecutors alleged that Allen Morgan, 73, and Margaret Morgan, 75, were in a "passionate, but forbidden and adulterous love affair" when they conspired to kill 36-year-old Carol Morgan, in 1981.

The couple, whose case is being heard in Luton Crown Court, denied participating in a conspiracy to commit murder, the BBC reported.

Prosecutor Pavlos Panayi alleged that the affair partners had regularly had sex in Margaret's home, while her then-husband was at work. Panayi told jurors that the defendants were unable to begin a legitimate relationship due to financial issues that prevented a divorce.

Instead "they both hatched [a plan] together in secret to arrange and pay for the murder of Allen's wife Carol Morgan."

Carol Morgan was found dead inside her shop - Morgan's Store, in Bedfordshire, England - one day after Allen allegedly took her children from a previous marriage to the movie theater. This was an unusual move for Allen because he did not have a "strong relationship with the children." The family's pet dog was also locked into a different room, the BBC reported.

"During their absence, Carol was alone in the shop. She closed the shop at 6 pm. After she closed, an attacker or attackers entered the premises and struck," the prosecutor said.

"Someone used an axe or heavy knife or machete to hack into her body and skull, causing horrifying injuries from which she died."

Allen Morgan contacted the police the following day, claiming that he found his wife dead and hundreds of dollars missing from the cash register. He was not considered a suspect because he was at the movie theater with the children.

A key witness for the prosecution came forward in 2021, decades after Carol was found dead. Jane Bunting, now 61, dated a man who was known to be a criminal as a teenager. Bunting alleges that Allen approached her in a bar, speculating whether she "knew anyone who could help him kill his wife," Panayi said.

The shocked teenager reportedly left the bar without giving Allen any information.

"We do not know who [the Morgans] eventually found," the prosecutor said. "That man may never be brought to justice."