Southeastern trains has a new critic: Boris Johnson.

The Mayor of London was due to appear in Dartford this morning to continue his campaign for Brexit, but was 30 minutes late after falling foul to rail delays.

He told the crowd upon his arrival at Europa Worldwide in Albion Road: "I apologise for being late, we have to take back control of Southeastern trains - it's about time TFL (Transport for London) were given the running here!"

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Hundreds of excited employees at the distribution firm had turned out to hear him encourage Brits to vote to leave the European Union (EU) on June 23.

"What a pleasure and a privilege to be here at this incredible firm Europa, which - of course - is the single market," said Mr Johnson.

"This is the absolute quintessential British success in Europe and will remain so in or out of the European Union."

VIDEO: Boris Johnson - a vote for Brexit is a vote for 'the restoration of freedom and democracy'.

Mr Johnson - widely tipped to succeed David Cameron at Number 10 - said that the UK was "big enough and strong enough to stand on its own" and it was time to "ignore the pessimists and the merchants of doom" fighting to keep the country in the union.

He continued: "If we had the self-confidence to take back control of our money, of our borders, and the ability of the people of this country to elect and remove the people who really take decisions about this country, then I think we would be able to take this country forwards with growth and opportunities that have absolutely nothing to do with EU bureaucracy."

Joking that as Mayor of London he sometimes tried to "lay claim to Dartford", Mr Johnson said the capital and surrounding areas were home to unrivalled technology innovations and creativity, and that successes like Europa were "nothing to do with the EU".

VIDEO: Boris Johnson drives a lorry around Dartford

Europa's managing director Andrew Baxter recently announced his support for leaving the EU, despite the company's 11 UK depots being connected to 28 hubs across the continent.

The facility in Dartford is one of the biggest in the UK, taking up almost 300,000 square feet of space at a cost of £30m.

"I believe that the most important factor for our business to succeed is that the UK economy succeeds," he said.

"I firmly believe that exiting the EU will help to protect the UK economy - helping our business to flourish and grow, and protecting jobs."

Responding to the train delay, a joint statement from Network Rail and Southeastern read: “We apologise to passengers who have been delayed this morning.

"A damaged power cable near London Bridge and an additional signalling problem near Lewisham has disrupted journeys from Charing Cross and Cannon Street.

“Network Rail engineers are working hard to fix the problems and we will work together to keep passengers informed.”