Sentencing of an Islamic State supporter who plotted to blow up St Paul’s Cathedral at Easter has been postponed after she was recorded in a prison phone call saying she had wanted to “go through with it” and had only been delayed because she had been “doing drugs”. In an unusual delay, an Old Bailey judge was told on Thursday that after Safiyya Amira Shaikh listened to what was said on her behalf in courtroom mitigation last week, she contradicted her lawyers and denied that she had got “cold feet”. Shaikh, 37, from Hayes, west London, has admitted preparing terrorist acts and disseminating terrorist publications. She discussed online, with co-conspirators who she later discovered were undercover officers, plans to target a hotel in the City of London and her desire to blow herself afterwards on the London Underground. Shaikh visited St Paul’s Cathedral to scout out security precautions and the best place to leave a bomb. She initially intended to carry out the attack at Christmas but later put it back to Easter. In court last Friday her defence counsel, Ben Newton, said she had been “having doubts” about the attack. She was eventually arrested on 10 October last year when she cancelled a meeting with undercover officers. But the transcript of a phone call she made to a friend from HMP Bronzefield at the weekend was read out in court on Thursday, making it clear she was unrepentant. Shaikh said: “I feel like this is a lie. I didn’t get cold feet … I was ready to go through with it. “My solicitor, they advised me to do this … I was ready to go through with it. I’m going to be honest with you cos when I read it [the press reports] I just think that I’m just a liar, yeah. “The reason that I didn’t turn up on the day is that I was doing drugs. I didn’t wake up in time. I would have arranged another appointment with them.” The court was told that the claims that she would not in the end have carried out the attack – a position she adopted in police interviews and that her lawyer later advanced in court – were “not correct”. The judge, Mr Justice Sweeney, who had been prepared to deliver sentence on Thursday afternoon, told the court that he would now have to consider the fresh evidence. He is due to deliver sentence at midday on Friday.