Travelers are expected to stand in long queues in the United Kingdom's busiest airports on Tuesday. A longstanding and unknown 'issue' with the Border Force led to chaos at Heathrow and Manchester Airport. Many other airports across the UK are also experiencing delays, leaving thousands of passengers stuck in the process of boarding their flights. The above-mentioned two airports confirmed that due to a persisting border issue, their services were affected.

A Heathrow spokesperson said: "Border Force is currently experiencing a nationwide issue which is impacting passengers being processed through the border.