The Wolverhampton-based group, which has pubs across the region, logged total pub revenue of £54 million during the 14 weeks ended January 2.
But Marston's said it remains optimistic for the future and believes that consumer demand will be “strong” when lockdown restrictions are lifted.
Pubs, restaurants and other leisure businesses have been battered by coronavirus-induced curbs, and their prospects were further hammered as Britain announced its third national lockdown earlier this week to counter rising Covid-19 cases involving a new coronavirus variant.
The two-century-old brewer known for its Pedigree, Hobgoblin and Lancaster Bomber beer, expects pubs to be closed at least until March as part of the latest national lockdown imposed across the country, with some restrictions to remain on reopening.
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The London-listed company said government support is being accessed through the job retention scheme, with 97 per cent of its employees currently furloughed and under business rates relief.
Under the government's support packages announced recently, hospitality and leisure companies would be able to claim one-off grants worth up to £9,000 pounds to get them through the coming months.
Ralph Findlay, Marston's CEO, said: “The pub sector has been closed for much of the last nine months and remains in a very difficult position.
"Regrettably there have been casualties across the sector and It is vital that the Government reviews urgently the opportunity to continue to support pubs as we reopen the economy in the coming weeks.
"Pubs are viable businesses which are part of the social fabric of Britain and which make a major contribution to the economy and the communities in which they serve. It is vital that they not only survive the short-term crisis but are supported in order to recover and flourish. Extending the business rates holiday and VAT cut for the rest of this year is a minimum requirement.
"Despite these challenges, Marston’s has a significantly strengthened balance sheet following the creation of the joint venture with Carlsberg and the financial headroom to weather the extended period of current trading restrictions.
"With the roll out of the vaccine programme now underway nationwide, we remain well positioned to rebuild trading momentum once restrictions are lifted, as well as to leverage potential market opportunities open to us. We have a clear strategy in place which leaves us confident for the future of our business over the medium term.”