Forecasted heavy snow fall and sub-zero temperatures has forced Greater Anglia to put in place a contingency plan which could see trains cancelled across Norfolk and Suffolk.

Weather warnings are in place for heavy snow from Monday and temperatures are not expected to get above freezing for the majority of the week.

Greater Anglia has said only key train services will run if two days of heavy snow and extreme weather conditions forecast for the east of the region materialise.

With forecaster Met Desk warning of up to 30cm of snow to fall, Network Rail will be concentrating on keeping main routes operating on Tuesday and Wednesday, including the Norwich to London Liverpool Street and Norwich to Cambridge lines.

MORE: Warning snow could cause rush hour delays in parts of Norfolk

If heavy snow does materialise there will be no services on rural routes including Norwich to Lowestoft, Great Yarmouth and Sheringham. There will also be no rail replacement bus service on these routes either.

Richard Dean, Greater Anglia train service delivery director said: 'We apologise for the inconvenience that this reduced service causes customers.

'The last time such heavy snow fell in this region was over 25 years ago. In extreme conditions such as these, we work hard with Network Rail to keep key routes open, using snow ploughs, points heaters and mobilising all staff to clear snow off platforms and heat up and de-ice trains.

'Volume of traffic on some routes keeps snow from settling too deep, like on roads, but not on rural routes. We are committed to keeping our customers safe in all conditions and the last thing anyone wants is for customers to be stranded on a cold train in the middle of a blizzard in rural Suffolk or Norfolk.

'If the forecasts prove wrong, we will of course, do everything possible to get services up and running as soon as possible.'

Other routes will run with a reduced service including between Ipswich, Colchester and London Liverpool Street due to slower speed restrictions.

Services on Monday will end at 10pm to allow trains to return to return to depots and stations before the forecast snow storms start. Services will start to be reduced by 8pm.

Some empty trains will run throughout the night to keep lines clear of snow for the morning commute.

On Tuesday and Wednesday, the reduced service will operate only between 6am and 10pm.

A Network Rail spokesperson added: 'We will be keeping a close eye on the forecast over the next few days and have plans in place should the extreme weather materialise.

'We will have extra staff working around the clock in order to keep main lines as clear as possible but while we will do everything we can to keep people moving, some lines may be closed and services will be subject to delays and cancellations, especially in the areas worst hit.

'We apologise for the inconvenience this will cause but the safety of our passengers and staff remains our number one priority.'