In relief for travellers, Britain has opened its borders to fully vaccinated people from the US and European Union as leaders urged the government to ease restrictions. The introduction of new rules came into effect amid reports that Prime Minister Boris Johnson's government may add a new category to its traffic light system. As of Monday, the fully vaccinated people from the destination on Britain's amber list can enter the nation without self-isolation for up to 10 days. The government will also create an amber list to warn people about the places that may be downgraded due to rising cases. Speaking to the media, Huw Merriman, chairman of the House of Commons Transport Committee, said they don't need any more uncertainty, complexity or anxiety for passengers as It just needs clarity. He also said British airlines and holiday companies are hoping for a late summer travel boom after the pandemic halted most international travel, slashing profits and threatening thousands of jobs. The number of passengers travelling through London's Heathrow Airport, the UK's busiest airport, fell 75% in the first half of this year. Travellers must take PCR tests to prove they are virus-free and countries including the US still bar foreign travellers from crossing their borders. Meanwhile, health authorities on Monday said they were tweaking the government's COVID-19 contact tracing phone app so that fewer people will be instructed to self-isolate following close contact with those who are infected. Health Secretary Sajid Javid said the app update, which will now check contacts for the past two days instead of five, will reduce disruption to people and businesses.