International travellers, including returning UK citizens, could face spot checks and £1,000 fines if they fail to self-isolate for 14 days after arriving in the country under measures to guard against a second wave of coronavirus. The home secretary, Priti Patel, is expected to outline the plans, which will be introduced early next month, at the daily Downing Street briefing on Friday, the Northern Ireland secretary, Brandon Lewis, confirmed on Friday morning. Exemptions for road hauliers and medical officials will apply, and the common travel area with Ireland and the Channel Islands will be unaffected. Arrivals from France will not be exempt, Lewis said, following confusion earlier this week. Travellers will be asked to fill in a form with their contact information, and health officials will perform spot checks to ensure compliance with the measures. Lewis told BBC Breakfast on Friday: “The reality is, we are saying to people, if you are going abroad, you need to look at the fact you may well need to quarantine when you come back. But this quarantine, when it comes in, it something we will be reviewing every three weeks or so. “I can’t say how long this quarantine will last for. That is something that will be down to the scientific advice at every stage as we assess it in terms of keeping that R level down.” Many other countries already require arriving passengers to enter a 14-day quarantine, including New Zealand, South Africa, South Korea, Spain and the US. This is despite the World Health Organization saying in February that measures that interfere significantly with international travel may only be justified at the beginning of an outbreak. The move will anger some sectors. Ryanair’s boss, Michael O’Leary, described the plan earlier this week as idiotic and unimplementable, and the Airlines UK trade body has said quarantine would “effectively kill” international travel to and from Britain. Lewis defended the timing of the new quarantine measures. Asked why the government had not implemented them sooner, he said: “As the virus spread is falling here in the UK as our R number is falling, obviously, that marginal impact of people coming in has a real effect in a way that it just didn’t a few weeks ago. And some weeks ago we were still returning many, many Britons back to the United Kingdom. “People who come over to the United Kingdom will have to do quarantine and a few countries around the world are looking at this or have already introduced this. There will be more details later on today. The home secretary will be doing the press conference at 5pm. As our R number is down we want to ensure that we don’t get that second spike that could be one of the most damaging things for our economy in the long run. “We’re a country a that welcomes people from all over the world. But it is appropriate that we say: ‘If you’re coming to the United Kingdom, we need to protect your own health and the health of the people of the United Kingdom.’ And the best way is to make sure that people go through that quarantine period to ensure they have no symptoms and are not able to add to the spread of the virus. “For UK citizens coming back, they will be able to go home and quarantine at home but for visitors they will need to make arrangements for where they can do that quarantine for 14 days.” Lewis played down an idea put forward by the transport secretary, Grant Shapps, for an “air bridge” to allow British holidaymakers to avoid quarantine. “There’s no plans for that at the moment,” he said.