The Army must demand both mental and physical fitness if it wants to legitimately claim to "be the best", the Duke of Cambridge has said, as he suggests it has been slow to implement full mental health training.

The Duke, who will one day be head of the Armed Forces, said he has "never really understood" why the Army had not always matched its physical training with mental health provision, ensuring soldiers are at their peak in all senses.

During a visit to Blackpool, in which he and the Duchess raised concerns about the plight of families living in squalor, he focused on the key issue of mental health throughout society.

Speaking to members of the emergency services, the Duke said more needed to be done around supporting their mental health and suggested he felt the both the “blue lights” and army have been historically slow to act.

“It’s totally understandable that those who work in the emergency services would at some point mental health issues build-up, because of the stuff that you see, the stuff you have to deal with and sort out," he said.

“If we can get the blue light community, the army and others to kind of be able to say 'this is essential'.