National Highways is advising drivers to allow extra time and plan their journeys in the South West ahead of this week's Glastonbury Festival.

Motorways and major A roads leading to the Glastonbury Festival are likely to be busy from Tuesday, 21 June to Friday, 24 June, as people make their way to Worthy Farm.

Drivers are advised that traffic is expected to reach its peak on Wednesday, particularly around junctions 25 and 23 of the M5, as festival goers make their way to the site. In previous years the A39 has been heavily congested by mid-morning. However, with festival car parks opening at 4pm on Tuesday - five hours earlier than in previous years - there is also expected to be increased traffic on Tuesday afternoon.

As usual, increased levels of traffic are also expected the day after the festival (on Monday, 27 June) as people leave the festival site.

The primary motorway route for festival traffic to the site is the M5, with drivers exiting at junction 23 to take the A39 and A361, while the A303-A37 is also used for traffic arriving from London, with the A303 eastbound expected to be particularly busy from Podimore Roundabout.

Levels of traffic are expected to be even heavier than usual because of this week's national rail strike which will see services severely reduced on Tuesday, Thursday and Saturday, with a knock-on impact on other days.

John Ingram, National Highways Emergency Planner for the South West, said: "We're reminding road users to plan ahead for Glastonbury – around 200,000 people are expected to attend this year's festival and roads leading to the event are likely to be very busy.

"Our aim is to keep the National Highways network running while keeping festival goers and other road users safe and informed. We advise people to check our traffic and travel information channels, but whatever your journey, we advise people to set off early and allow plenty of time.

"And with temperatures expected to remain warm through the week, we'd also advise pre-checking your vehicles for oil, fuel and coolant levels and correctly inflated tyres, also to ensure you have plenty of drinking water with you to stay hydrated."

Here is the outlook for the next few days:

- Tuesday 21 June: Festival car parks open at 4pm (5 hours earlier than before) so expect increased car traffic

- Wednesday 22 June: Festival gates open at 9am. Expect increased traffic

- Thursday 23 June – Sunday 26 June: Expect relatively normal traffic volumes

- Monday 27 June: Festival ends. Outbound traffic plan in place as per previous years

Real-time traffic information for England's motorways and major A roads is available from the web at www.trafficengland.com or (when not driving) from a phone or mobile device at m.highways.gov.uk. Information is also available via local radio updates and also on Twitter at @HighwaysSWEST.