A pedestrian has died after being hit by a tree that fell into a road as the remnants of Hurricane Gonzalo brought high winds to Britain.
The woman died at the scene in Kensington, west London, London Ambulance Service said.
A spokeswoman said: "We were called at 11.40am to reports of a tree fallen on a person on Kensington Road.
"We sent an ambulance crew, a responder by car, an advanced paramedic, a medical team from London's Air Ambulance by car and a duty officer to the scene.
"Sadly, despite our attempts to resuscitate the patient, a woman died at the scene."
The London Fire Brigade also attended the incident and was working to remove the tree.
The incident took place as the Duke and Duchess of Cambridge were meeting president of Singapore Tony Tan Keng Yam and his wife nearby at the start of their state visit.
The meeting, at the Royal Garden Hotel in Kensington High Street, was Kate's first official engagement since it was announced she is expecting her second child.
The stormy conditions also led to three women being injured by a fallen tree at Southwick Recreation Ground in West Sussex just before 10am.
The three, one of them believed to be in a wheelchair, were taken to hospital.
Strong winds brought down trees on railway lines, while more than 100 flights had to be axed at Heathrow airport and driving conditions were particularly bad in Scotland.
Some areas were subjected to gusts of wind up to 65mph, but forecasters predicted that the worst of the weather would be over after today.
In Scotland, where heavy rain led to poor visibility on the A90 south of Aberdeen, the Forth Road Bridge, the A87 Skye Bridge and the A898 Erskine Bridge were closed to high-sided vehicles.
In England, a section of the A1(M) in Cambridgeshire was closed due to an overturned lorry and there was heavy traffic on a number of motorways and A-roads, with Cheshire among the worst-hit counties.
On the railways, a combination of broken-down trains and stormy conditions resulted in delays and cancellations on a number of lines.
Among the areas where passengers endured delays were East Anglia, south east London, Cheshire, Hertfordshire, Somerset and Devon.
Flooding in Wales meant buses had to replace trains between North Llanrwst and Blaenau Ffestiniog, with the disruption likely to last for the rest of the day.
A Network Rail spokesman said: "Strong winds, torrential rain and large quantities of fallen leaves are making conditions difficult on the railway today.
"Just like motorists on the roads adapt their driving style to the conditions, train drivers are having to take extra care accelerating and braking to avoid overshooting platforms or signals."
He went on: "Our fleet of special leaf-busting trains are working to keep the rails clear of slippery leaf mulch and, where the railway is prone to flooding, we've made sure pumps are clear and in full working order should they be needed.
"We're working closely with train operators to keep people moving and have response teams ready to clear fallen trees and any other debris blown on to the tracks. In some locations, speed restrictions are in place so trains can stop in time if an obstruction is spotted."
A number of ferry crossings between Holyhead in North Wales and Dublin were cancelled due to the adverse weather, said Irish Ferries.
By 2.30pm today, the AA had attended more than 5,400 breakdowns, currently coming in at around 730 every hour.
John Seymour, national manager of the AA's severe weather team, said: "It's helped that Tuesday is the quietest weekday for travel. Although the wind and rain have created difficult driving conditions at times, we haven't seen an increase in call-outs.
"However, it's still pretty windy out there, so drivers should exercise care on the journey home this evening, as there could be debris on the roads and leaf-fall can make them slippery. If your car is being buffeted by the wind - slow down, as the faster you drive, the further off course you can be blown."