The Sunbury track, also due to stage the Silviniaco Conti Chase, had been frozen all week, but clerk of the course Barney Clifford, speaking on Thursday afternoon, reported a “remarkable” improvement in the past 24 hours.

Compounding matters is Storm Goretti blowing in, with up to 20 millimetres of rain forecast which could fall as snow.

Clifford said: “I’ve called a second inspection because there’s still a bit of a bone to it and there are areas of concern.

“Although we got up to 6C yesterday it still felt like -3C but today although it’s only got to 5C it actually feels like 5C so I’ve had one jacket less on walking round.

“We’ve seen a remarkable improvement in the past 24 hours, but taking into account the forecast and this snow bomb that could end up anywhere, I think it’s prudent to have a look at 2pm tomorrow to keep everyone in the loop.

“I’m more optimistic today than I was yesterday, but I had to see that improvement because previous to that it was like concrete.

“They say for every day you have frost you need another day for it to come out and that rule of thumb is proving accurate.”

Warwick’s Classic Chase card must also survive a 2pm inspection on Friday.

While there had been a good deal of improvement on Wednesday, that had slowed down on Thursday and there is the risk the forecast up to 25mm of rain could fall as snow.

Nessie Chanter, clerk of the course, said: “We’ve had a foggy day today so we haven’t seen much movement meaning we’re still frozen in places.

“We are due quite a lot of rain tonight and we are hoping that remains as rain, if it does turn to snow it will be preceded by more rain. That’s 20-25mm tonight.

“We’ll know a lot more in the morning and we’ll inspect at 2pm.”

Southwell’s jumps meeting on Friday went by the wayside after an inspection on Thursday afternoon with the course still unraceable in places, while Wolverhampton’s all-weather card on Friday will need to pass a 9.30am inspection due to the possibility of snow.

Officials at Huntingdon made an early decision regarding their Friday card, which was due to feature the Chateris Fen Juvenile Hurdle, and after failing a 9am inspection the meeting was abandoned.

Exeter passed an inspection on on Thursday morning but called a precautionary 8am check ahead of racing on Friday. The course is raceable but there are weather warnings for wind and snow in place overnight.

Sunday’s meeting at Kelso has been abandoned due to a frozen track. In Ireland the rescheduled Grade One card at Naas must pass a 7.30am inspection ahead of racing on Friday.

Meanwhile, the British Horseracing Authority has announced an extra meeting will be staged at Chelmsford on Sunday on the all-weather.