The within-day rose by 0.l0 pence to 21.50 p/therm by 0940 GMT.
UK March contract fell by 0.35 p to 20.80 p/therm.
"Trading is quiet because it's a half-term break and lots of people are out," a trader said, adding that liquidity is expected to remain reduced this week.
UK gas system was 23.3 million cubic metres (mcm) undersupplied, with demand expected at 262.2 mcm and supply at 238.9 mcm, National Grid data showed.
After storm Dennis hit Britain last week, wind generation is expected to remain robust, which tends to reduce gas-for-power demand.
"UK wind power generation is forecast to remain above normal until late February with a slight drop in the middle of this week," Refinitiv analysts said in a morning note.
On Monday, peak wind production was forecast to reach 14 gigawatts (GW) out of 17.9 GW wind generation capacity, edging down to 13.5 GW on Tuesday, Elexon data showed.
Monday gas-for-power demand was expected to be 17 mcm, lower than an earlier forecast and was predicted to rise slightly on Tuesday.
Residential demand was expected to edge up on Monday compared with Friday, but the forecast was reduced by 34 mcm from an earlier prediction, Refinitiv data showed.
Residential consumption could be reduced later this week as temperatures are expected to rise, the trader said.
On the supply side, there was a strong drop in liquefied natural gas (LNG) sendout. A total of 61 mcm was forecast to be sent to the gas system, a 40 mcm drop from Friday volumes, data compiled by Refinitiv showed.
Other supply sources were stable, with flows from the UK Continental Shelf expected to be at 129 mcm/day and imports from Norway at 63 mcm/day.
On the Dutch market, the day-ahead price was down 0.40 euro at 8.75 euros per megawatt hour (MWh).
The March gas price at the Dutch TTF hub was down 0.20 euro at 8.73 euros per MWh.
The benchmark Dec-20 EU carbon contract was down 0.08 euro at 24.29 euros per tonne.