The reduction was implemented from 6pm on Wednesday and will last until March 2023, although figures from data firm Experian Catalist show the average cost of a litre of petrol at UK forecourts on Tuesday was 167.3p, while diesel was 179.7p.
We took a look at some pump prices before and after the reduction came into effect to see if retailers were reducing their prices.
Whilst some retailers have said the 5p cut will be reflected in their prices, not all stations have reduced prices by the amount Mr Sunak announced in his Spring Statement, with one fuel station instead raising its diesel price by 5p.
Tesco on Marston Road, Wolverhampton had prices of 161.9p per litre of petrol and 169.9p per litre of diesel on Wednesday, and this morning had reduced its price for petrol by 6p to 155.9p per litre of petrol. However, diesel was down just 1p to 168.9p per litre.
When queried on the price changes, and asked why diesel was reduced by just 1p a staff member said: "We don’t decide the prices ourselves (the staff).
“Head office lets us know what the prices change to. They send the prices to our tills and we then change it to whatever price they send us.”
The fuel prices at BP on Wolverhampton Road, Sedgley were unchanged when visiting before and after the cut came into effect. Their prices were unchanged at 165.9p per litre of petrol, and 175.9p per litre of diesel.
Meanwhile Shell on Birmingham Road in Wolverhampton had reduced both its prices of petrol and diesel by 5p. Before the fuel duty cut petrol was 167.9p per litre. On Thursday morning it was 162.9p per litre. Diesel at the filling station was down from 182.9p per litre to 177.9p per litre.
However, Texaco on Willenhall Road in Bilston has raised its price of diesel from 177.9p per litre to 182.9p - a 5p hike despite the 5p fuel duty cut coming into effect.
When asked why the diesel price has increased by 5p rather than being cut by the same amount, a staff member said: "They (Texaco) change the price daily.
"They fix the price and we are a franchise that receive their price and change it to what they tell us."
The garage kept its petrol price the same at 164.9p per litre.
Motoring groups reacted cautiously to Mr Sunak's announcement on Wednesday.
AA president Edmund King said: “The AA welcomes the cut in fuel duty. However, we are concerned that the benefit will be lost unless retailers pass it on and reflect a fair price at the pumps.
“Average pump prices yesterday hit new records despite the fall in wholesale costs."
Steve Gooding, director of motoring research charity the RAC Foundation, said the duty cut “doesn’t go very far to help low-wage key workers who rely on a car to get to their place of employment, often at times which are antisocial and when other travel options are non-existent”.
Rod McKenzie, executive director at the Road Haulage Association, described cutting duty as “a common sense move” that will “be a boost for the economy”, but he warned “more could have been done”.
He said: “The Chancellor missed an opportunity to announce a rebate to relieve more pressure on businesses.