The shop owner, Keith Radford, stands to clean up should the post office fold through loss of revenue because of the Government's plan to encourage pensioners and others to have benefits paid directly into their bank accounts, saving the Treasury millions of pounds.
But the existence of the village post office is not entirely about money, even for Mr Radford, who takes the long view. 'It's the focus of the village. If you take that away, you take the heart out of the village. It's not like a shop in a town or a city where you dash in and out and no one knows anybody. A lot of people here make shopping trips an excuse to talk to friends about what's going on, how and why.'
But even in purely financial terms there is a rationale behind Mr Radford's rearguard action on behalf of his competitor.
If the people of Ditchling (pop 1,500), East Sussex, were to collect their pensions and benefits elsewhere - perhaps Hassocks, three miles distant, or Burgess Hill - then, the argument runs, they would be much less likely to spend their money locally in the butcher's, baker's or even the newsagent's.
'The village shops are here to serve the people,' said Mr Radford, who has lived there for four years. 'If you take one or two of them away it is unlikely that the people would use those that are left.'
Economic considerations are uppermost in Jill Holmes's mind. As the postmistress of eight years' standing, she is acutely aware that any reduction in her salary - based on the number of transactions - could mean the slow bleeding to death of the whole enterprise.
For each of the 398 pensions she passed over the counter last week she will receive 7p, and a further 3p for the 98 family allowances handed out. Less numerous, but possibly more important socially, are the other benefits, which fall into three broad categories: sickness, invalidity and widow's. Inevitably, almost everyone picking up weekly allowances posts some mail, or buys television or telephone stamps, keeping business ticking over. The rows of boiled sweets and chocolate bars lining the shelves opposite are a further temptation to spend.
'Without the post office I don't think the shop would be viable in the long term,' Mrs Holmes said. 'We used to deliver newspapers, but stopped after we took over the post office when the previous postmaster retired.'
The financial aspects are vital, but ultimately only the nuts and bolts of a business that has a much wider role. At its most significant it is a surrogate for the local authority social services.
Mrs Holmes tells a tale to illustrate the point. 'There was one old boy who lived on his own. He was the type that was always first in the queue at 9am. But at the start of last winter he hadn't been up for a week or two and I called the social services at Lewes. It turned out that he had got very low and had pneumonia. We got him a home help and he's fine now.'
But, for most, it is simply a place to get a piece of advice (filling in of poll tax forms kept Mrs Holmes busy for months), catch up on the gossip, or simply to provide a reason to go out. Nelly Hill, 92, said: 'It gets me out of the house, which is important at my age, especially in the winter. I don't know what I would do without it.'
After questioning Mrs Holmes on how she should go about getting a rent rebate from the council, Betty Foster, 72, who has lived in the village all her life, said that she was under no illusions as to what life would be like without the post office.
'I'd have to go to Hassocks. But the bus service is terrible and it's 40p each way. How would I manage?'
Grace Rutherford, 82, was practically spitting with anger at the Government's money-saving plans. 'They seem to think that money is more important than people,' she said, eyes flashing.
'It's so unjust. And all just to save a few bob. But I think they've picked on the wrong thing this time. It would be catastrophic if it closed down. I would certainly go and beard the people in Parliament.' She might not be alone.Reuse content