The security alert was downgraded to severe from critical across Britain

. Mobile phones are allowed back on planes, and as of Tuesday, passengers also may bring laptops and other electronic devices in one small carry-on, officials said. They warned passengers that "the security regime is still more onerous" than before last week's emergency, and that the ban on liquids and gels in carry-on bags continues. Due to the continued restrictions, BAA Airports officials said 68 flights (about one-third of total departures), were cancelled at Heathrow. As of Tuesday, passengers may carry onboard a bag no larger than 17.5 x 13.5 x 6 inches for flights at Heathrow.