A homeless man approached air cadets in the Bulwell branch of McDonald's and said he wanted to drop a nuclear bomb on London.
Mohammed Dar told them he hoped to join the Russian Army and wanted them to declare war on England, Nottingham Magistrates' Court heard.
Dar, 57, said: "I want to push the red button and nuke bomb London.
"I am not concerned my mother lives in London."
Sanjay Jerath, prosecuting, said: "He stated he thought the British Army was a waste of money.
"He said that he wanted to get a letter to Putin and that he wanted a war between England and Russia, saying that he will fight for Russia.
"He approached the couple in McDonald's because they were wearing military uniforms."
When questioned by a police officer, Dar told him: "I hate this country. I will fight for Russia.
"I will press the nuclear button for Russia against England. I want to die for a war on liberty, it is a glorious thing to do. I crave it."
The court heard Dar is already subject to an anti-social behaviour order which bars him from causing alarm or distress.
He admitted breaching this order and also two public order offences in Bulwell on Sunday, July 7.
Rob Keeble, mitigating, said Dar wanted to go to prison and told the court: "He was very candid with the police.
"Although he gave a rather skewed explanation, he said that he did it to cause alarm and offence.
"It is a troubling case, most unusual," added Mr Keeble.
District Judge Leo Pyle sent Dar to Nottingham crown court to be sentenced later this month. When told he would be remanded in custody, Dar said: "Thank you."
He had been seen by a psychiatric nurse who told the judge: "Mr Dar is fully aware of what he was doing and the impact of what he was doing in terms of alarm and distress.
"He used it as a way to return to prison."
