Major disruption has hit rail services connecting central London to Heathrow Airport after a grass fire forced all trains to halt. The blaze, which broke out near the airport, has caused severe delays and cancellations, with no services operating between the city and the airport. Passengers are advised to check for updates as the situation remains unclear. The fire is believed to have started in a grassy area near the airport perimeter, though the exact cause is under investigation. Emergency services are on-site, and efforts are ongoing to clear the area and restore rail traffic. Travelers are urged to seek alternative transport options due to the ongoing disruption. The incident has raised concerns about the vulnerability of transport infrastructure to such incidents, prompting calls for improved emergency response protocols.