A builder has told how his pregnant wife’s ex-husband smiled and gave a thumbs up before he allegedly shot her dead with a crossbow.

Imtiaz Muhammad had got together with 35-year-old Devi Unmathallegadoo after her arranged marriage with Ramanodge Unmathallegadoo, 51, broke down.

Unmathallegadoo, known as Ram, became obsessed with getting revenge on them over the course of a year, spying and assembling a cache of weapons, the Old Bailey has heard.

On the morning of November 12 2018, he had allegedly taken up position in his wife’s garden shed, awaiting his moment to strike with two new crossbows, bolts, a hammer, a knife in a homemade sheath, cable ties and duct tape.

The defendant shot Mrs Unmathallegadoo as she attempted to flee upstairs at the family home in Ilford, east London, the court heard.

Mrs Unmathallegadoo suffered devastating internal injuries and died but her unborn son was delivered by caesarean section and survived.

Giving evidence, Mr Muhammad became emotional as he told jurors: “My brain was frozen. I did not know what was happening. Is it real? I’m dreaming.”

He said his wife, also known as Sana, had got up early that day to start cooking for friends.

Mr Muhammad said he did his bit to prepare for visitors by taking an empty television box to the shed.

He heard a noise behind his back and turned around to find the defendant carrying one crossbow over his shoulder and another in his hand which he pointed up, he said.

The defendant smiled at him and gave a thumbs up, Mr Muhammad said: “I was super shocked and I did not know what to do. I stayed there for 10 seconds then I ran out. Then he was running behind me through the garden.

“I’m saying to my wife ‘run out’. She could see what was happening in the garden. She screamed and she started running through the corridor.

“I ran through the living room. When I stepped out of the porch I turned back thinking ‘where is my wife’. I see my wife, she’s running up the staircase. Ram was coming through the corridor with the crossbow.”

The witness told jurors the defendant turned and faced the staircase, brought the crossbow up and shot his wife.

He said: “He did not waste a second. He seemed like he had training.”

Mr Muhammad told jurors the bolt entered his wife’s body so he could only see the end of it.

He went on: “When he was coming in the corridor I was in front of him but he was not looking at me. He was focused on her.

“When she got an arrow she just screamed. I was thinking, ‘what is happening?’, I was screaming for her.

“Then from there, because he had a second crossbow on his shoulder, I was thinking he’s used one and now the second one might be for me.”

Mr Muhammad shouted for the police to be called and the defendant came out with his hands up, jurors heard.

The defendant, formerly of Ilford, has denied murder and the attempted destruction of the unborn child.