Alex Younger (pictured speaking today) told St Andrews students that MI6 is improving its defence against states such as Russia

The head of MI6 has raised concerns about Chinese companies building high-speed mobile internet networks in the UK.

In a rare public appearance, Alex Younger said Britain needs to decide ‘the extent to which we would be comfortable’ with the Chinese owning our future high-speed internet networks.

China is currently a world leader in developing 5G, a next generation mobile internet technology that promises to deliver much faster download speeds which could revolutionise connectivity.

Speaking to students at St Andrews University, his alma mater, Mr Younger - who is known by the codename ‘C’ - said: ‘I think this is really interesting. We’ve got some decisions to take.

‘This is about how 5G will, by and large, be based on Chinese technology.

‘We need to decide the extent to which we are going to be comfortable with Chinese ownership of these technologies and these platforms in an environment where some of our allies have taken quite a definite position.

'We need to have a conversation, it is not wholly straightforward.’

Australia and New Zealand have both recently banned Chinese telecoms firm Huawei from providing 5G equipment on national security grounds.

The Australian government said there were concerns about the country’s internet networks being provided by companies ‘likely to be subject to extrajudicial directions from a foreign government’.

Alex Younger, the head of MI6, has today warned Russia and others 'intent on subverting our way of life' not to underestimate Britain

The technology, which will supersede the current 4G, could speed up the creation of ‘smart cities’ in which everything from traffic signals to driverless cars are linked.

Mr Younger, who was giving only his second ever public speech since becoming head of MI6 in 2014, said the UK must adjust to a new political reality as ‘power, money and politics are going east’.

He also raised the prospect of a technological arms race, saying that the evolving threat from nation states comes largely from their ‘increasingly innovative exploitation of modern technology.’

He added: ‘So simply put, we’ve got to innovate faster than they can. Indeed, future generations would not forgive us if it were otherwise.

‘So we are evolving rapidly. Cyber is now our fastest-growing directorate. We are shifting our focus to the nexus between humans and technology.

‘But my organisation will need to adapt even faster if it is to thrive in the future. And that will require people with new perspectives, capable of harnessing their creativity in ways that we can’t yet even imagine.’

However, Mr Younger stressed that human intelligence - gathered by agents in the field - will become more, rather than less, important in the digital age.

He also said that, post-Brexit, Britain will continue to work with allies because our security ties in Europe are ‘indispensable’.

Mr Younger said that closely working with European intelligence agencies had prevented ‘multiple’ planned attacks by ISIS which would have resulted in a ‘significant loss of life’.

He said that, as a result, MI6 agents had lost their lives doing the ‘exceptionally difficult and dangerous work’.

‘Our country and our allies owe them a debt they can never truly know and never fully repay,’ he said.

Mr Younger said that Britain's response to the Salisbury nerve agent attack was designed to attach a cost to 'malign behaviour' (pictured Salisbury Cathedral)

In the wide-ranging speech, he also said he was left ‘perplexed’ by the jailing of British academic Matthew Hedges for spying in the United Arab Emirates.

He was freed last week after a high-profile battle with the Gulf state ally, but officials persisted in calling him an MI6 spy - a claim denied by family and colleagues.

Mr Younger said: ‘I genuinely don’t understand how our Emirati partners came to the conclusions they came to. They are important partners of ours, so I think there are some frank conversations ahead of us.’

He also said ‘frank conversations’ were needed after the killing of the journalist Jamal Khashoggi in an attack which he described as ‘shocking’ and ‘appalling’.

The boss of MI6, also known as the Secret Intelligence Service, also used his speech to single out Russia and the ‘flagrant hostile act’ of the Salisbury nerve agent attack against Sergei Skripal and his daughter Yulia in March.

He said that MI6 will no longer take the state at its word, adding: ‘Mr Skripal came to the UK in an American-brokered exchange, having been pardoned by the president of Russia - and to that extent we assumed that had meaning.

'That is not an assumption we will make again.’

Mr Younger described how MI6 helped expose the perpetrators said to be behind the attack, and how it helped co-ordinate the expulsion of Russian diplomats.

He said: ‘Our intention is for the Russian state to conclude that, whatever benefits it thinks it is accruing from this activity, they are not worth the risk. ‘We will do this in our own way, according to our laws, and our values.

‘We will be successful nonetheless, and I urge Russia or any other state intent on subverting our way of life not to underestimate our determination and our capabilities, or those of our allies.

‘We can do this to any opponent at any time.’