Michael Fallon, the defence secretary, has sought to assure MPs that the surprise deployment of UK military trainers to Ukraine will not lead to mission creep.

“We are not deploying combat troops to Ukraine and we will not do so,” he said.

“We should come to the help of a friend in need.”

There was no military solution to the crisis in Ukraine, he added.

Fallon also revealed the Ministry of Defence was looking at a separate requests from the Ukrainian government for all kinds of equipment, but stressed that at this stage it would be non-lethal.

He said he was looking at the shortfalls in Ukrainian equipment and the need for any additional training that went beyond Tuesday’s announcement.

He implied that much of the equipment sought by the Kiev was lethal, but pointed out that a lot of their weaponry was from the Soviet era and did not easily dovetail with UK equipment.

Fallon said the UK taxpayer would be responsible for the cost of the training and any gifting of equipment.

“This is not a Nato deployment, this is a decision of the UK government,” he said. He remained vague about whether he had consulted Britain’s Nato allies before David Cameron made his announcement to a committee of MPs on Tuesday.

The prime minister revealed he was sending as many as 75 military trainers to Ukraine to cover logistics, intelligence, medical aid and infantry training. The bulk of the training would take place in western Ukraine, away from the front line.

Liam Fox, the former defence secretary, was one of a small group of MPs who pressed Fallon to reconsider his opposition to providing lethal weapons, saying Ukraine was in need of drone reconnaissance, anti-tank capability and encrypted communications systems.

He said that if the UK shied away from providing such equipment it would be seen as “a bullies charter”.

Fox added that Britain could not leave the defence of Europe to the US, but that it was important that Nato played its role in defending its borders.

Rory Stewart, the defence select committee chairman, welcomed the deployment.

“It’s certainly a change, it’s really a sign that as the current ceasefire agreement seems to be fraying, Britain and the US and Canada and others are prepared to provide support for the Ukrainian government and I think that’s the correct thing to do,” he said.