Boris Johnson is to be the keynote speaker at the blockchain conference in Singapore | Boris Johnson

Boris Johnson is heading to Singapore, on the last of his post-prime ministerial tour, to keynote a conference on blockchain.

The former Prime Minister, who pulled out of the race to replace Liz Truss last week and remains the MP for Uxbridge and South Ruislip, will deliver the keynote address at the International Symposium on Blockchain Advancements on December 2.

Blockchain technology is used to provide a secure way to make and record transactions, most commonly for the cryptocurrency bitcoin.

Dick Cheney, former Vice President of the United States, also speaks at the conference. The conference’s website says it “aims to guide the first step in the migration to the digital economy by provoking meaningful questions and discussions that will enable all of us, builders and consumers alike, to cut through the blockchain hype and gain a realistic view of the new trends and needs, and to provide a technical plan for innovative solutions”.

In September, Johnson was paid £130,000 to give a speech at the Council of Insurance Agents and Brokers in Colorado, where he joked about sharing French President Emmanuel Macron’s “fancy” wine with Angela Merkel.

On Tuesday, Johnson told Sky News he would be “very happy” to go to the Cop27 climate summit after being “invited by the Egyptians”.

Asked if Rishi Sunak should also attend, he said the new prime minister will have a “massive lot to do”, adding: “I happen to have a special interest.”

Two government sources told the Guardian that Sunak was now planning to attend the conference, after being accused of showing “leadership failure”. But No 10 said the decision was still “under consideration”.

Johnson told Sky it had become “unfashionable” to talk about Cop26, which he hosted in Glasgow last year.

Asked if he felt more appreciated on the world stage, Johnson added: “I have an absolutely passionate belief that the war in Ukraine, Putin’s act of aggression is something that we should not accept. I think I can continue to campaign for Ukraine, and that’s what I’m going to do.”

Speaking to Sky from the Imperial War Museum, Johnson also said Vladimir Putin would be “crazy” to use a nuclear weapon in Ukraine, claiming the move would “immediately call for Russia’s dismissal from the club of civilized nations”.