Chris Grayling has denied reports that his department is preparing to lay on emergency freight services across Kent in the event of a no-deal Brexit.
The Transport Secretary was grilled in the Commons over reports that the Government was in talks with two foreign-owned rail freight giants to run services from April to guarantee the flow of food and medicines.
Labour MP Lilian Greenwood, who chairs the Commons transport committee, asked Mr Grayling if commuters in Kent should be "bracing themselves for possible disruption".
She said: "It's been reported his department is in talks with two rail freight companies about options to provide additional services via the Channel Tunnel and HS1 to ensure supplies of food and medicine in the event of blockages at Kent ports.
"It's also claimed the department had written to Southeastern trains warning of possible disruption to their services if additional daytime freight movements are required.
"Is his department really contemplating emergency rail timetables in the event of a no-deal Brexit, has he written to Southeastern regarding such contingency plans, and should the many thousands of rail commuters in Kent be bracing themselves for possible disruption?"
Mr Grayling replied: "No, the story is untrue."
'Richard Branson says he has never met you'
Labour MP Barry Sheerman challenged Transport Secretary Chris Grayling on his assertion he had met with all the major UK airline chief executives.
He was later accused of not doing enough to make sure safety agreements are in place to allow airlines to keep operating if there is a no-deal Brexit.
Labour said the Transport Secretary had failed to come up with an alternative if the UK drops out of the European Aviation Safety Agency (EASA) because there is no agreement with the EU.
Barry Sheerman, the MP for Huddersfield asked Mr Grayling to name the airlines he had spoken to about this.
He said: "I challenged his colleague to tell me which chief executive or chair of any airline that he's talked to about this.
"I've talked to them, they're terrified of the impact of going out on no-deal Brexit. He couldn't name one."
Mr Grayling replied: "I've talked to the chief executive of every major UK airline, I've also talked to representatives of a number of international airlines."
Mr Sheerman heckled him, asking: "When did you meet Richard Branson? Richard Branson says he's never met you."
Shadow transport minister Karl Turner said: "The Prime Minister's deal looks dead and we could well be heading into the chaos of a no-deal Brexit.
"If that is the case we'll no longer be a member of EASA and, given that we do not currently have a bilateral safety agreement in place with the US, can the minister give a guarantee that in the event of no deal there will be no disruption to flights?"
Mr Grayling said he could and the Civil Aviation Authority was working on a "properly functional British alternative".
'Unprecedented' Gatwick drone attack
A 'No Drones' sign alerting members of the public that the use of drones or unmanned aerial vehicles (UAV) is prohibited.
Mr Grayling was also questioned about the recent suspected drone sightings at Gatwick and Heathrow airports, and whether the UK was prepared to deal with such attacks.
Labour MP John Spellar questioned: "I am sure that the Secretary of State can chew gum and walk at the same time so while he is dealing with the viability of the future of leaving the EU, can he also deal with the current crisis of drones affecting teh airport?
"Can I give him the opportunity to answer the questions he did not answer earlier in the week: Were there contingency plans already agreed with the Ministry of Defence and Home Office to protect our airports from drone incidents and others? If not, why not?
"Were such plans not activated in time because of dithering? Why did they not work? Was that the fault of the Secretary of State's department, Ministry of Defence, Home Office or the Cabinet Office?"
Mr Grayling responded that he would remind the MP for Warley of "two factors".
"Firstly that the disruptive attack on Gatwick was unprecedented anywhere in the world. As a result, we have been approached by airports around the world to learn about how we tackle that.
"Secondly, I would point out that I am not able to discuss the nature of the technology that was used in this house for security reasons.
"But, you will have seen earlier this week Mr Speaker, that when a similar issue arose at Heathrow the response was very rapid indeed."