Volodymyr Zelensky’s victory plan will be “defining” for the next period of the conflict in Ukraine, Defence Secretary John Healey has said.

Speaking at a fringe event at the Labour Party conference in Liverpool, Mr Healey also said the UK will support Ukraine “at any point when they decide they may want to stop” fighting and announced a joint specialist unit between his department and the Foreign Office to facilitate aid.

The Ukrainian leader is set to address the UN General Assembly on Wednesday and will present President Joe Biden with a “victory plan”.

The plan is set to include long-range striking capabilities and other weapons long sought by Kyiv, and will serve as the basis for any future negotiation with Russia.

Mr Healey told the event at conference that what is next for Ukraine “is going to be defined for us all if President Zelensky delivers what he’s trailed” in his promise to turn up in New York with a victory plan.

He said: “Why is that important? It isn’t just important because the Ukrainians are the ones who are fighting, the Ukrainians are the ones who have the right to call a stop, and our task is to support them in their fight and then to support them at any point when they decide they may want to stop.

“But it’s important for this, and it is something that I have urged on President Zelensky, as others have, and on his defence minister in the seven times I think that he and I have met in the last two months since I got this job and before.

“But if we – Ukraine’s close allies – have a better idea about their plan, then we’re in a better position for us to be able to plan how we can support not just the immediate provision of help, but the long term production.

“Not just the immediate training of their troops, which we will do, but how do we equip them for the future to be a force that can protect themselves in the future.

“So I see this meeting at the United Nations, and the potential contribution that President Zelensky is promising as defining for this next period ahead.”

The Defence Secretary said what victory for Ukraine will look like is for Ukraine to decide, but that it is “absolutely preventing Putin from prevailing”.

He further stated: “We need to do more than simply provide the military support, and that we are announcing today the setting up of a joint Foreign Office and MoD (Ministry of Defence) specialist unit on Ukraine.

“It’s partly a reflection of the joint work that David Lammy and I have done in and on Ukraine and joining the two departments, but its importance is that it signals for UK Government and its more widely what we need to do is military, economic, industrial, diplomatic – Ukraine needs our support on a number of fronts, and we’ve not been doing that.”

Mr Healey described the Ukrainians incursion into Kursk as “an open wound for Putin” and a reminder that their military “still have the capacity to spring battlefield surprises”.

Mr Zelensky has repeatedly called on the US and UK to allow Ukraine to use long-range Storm Shadow missiles inside Russian territory, a request that has so far been declined.

On granting permission for Storm Shadow missiles to be used in Ukraine, the Defence Secretary said: “I take quite a simple view of this debate about specific weapons, which is that the more that we do that the more that we play into Putin’s hands.

“I think Putin is the only one who benefits from that sort of debate.”

He added: “In general, we’ve donated weapons to Ukraine for their defence and as long as those are used within the balance of international law and therefore in self defence that does not, in general, preclude strikes on Russia.”

The Prime Minister’s deputy official spokeswoman has said the position on whether Ukraine would be given permission to fire Storm Shadow weapons in Russia “remains unchanged”.

In its election manifesto, Labour said it would reach 2.5% of GDP spending on defence, a pledge Mr Healey affirmed “will happen”.

He said: “You will not find any other manifesto commitments to reform mechanics in Government like we had on defence for any other realm, and you will not find a spending commitment like we have for defence in any other departmental area.”