The Crewe part of the Crewe & Nantwich constituency is the larger and more famous, but it is the Nantwich part which has by far the longer and most interesting history. It was an important centre for the production of salt from Roman times. It was thus something of a prized location, but had a troubled history as a consequence. The Normans attacked it on their arrival in England, leaving just one building left standing. A couple of centuries later it was destroyed by bandits from across the Welsh border. In 1583 it endured a Great Fire which raged for 20 days, and had to be rebuilt at the staggering cost of £30,000 in 16th- century money.

A similar fate appears to await the Labour Party in the parliamentary by-election there in ten days' time. On this occasion it is the Conservatives rather than the Normans, Celts or flames who are poised to inflict the damage. Salt will be rubbed into the wounds of the local election debacle. The manner of the likely Tory triumph, furthermore, will add insult to injury.

For the Conservative campaign in this corner of Cheshire is absolutely shameless. Voters are being urged to “send Gordon Brown a message over the abolition of the 10p tax band”.

This is despite the fact that Conservatives, who naturally favour a simple tax system with a small number of rates, should instinctively support Mr Brown's reform. It is also disingenuous - David Cameron has not himself pledged to restore the 10p level but is urging the Prime Minister to “reopen the Budget” as if the Finance Bill is the equivalent of a child's dressing-up box. The underlying sentiment - that lower income workers should look to him for salvation - is debatable. “Save the poor, vote Tory” has the ring of “Save the whale, vote Harpoonist” about it.

The broader economic argument that is being sold is no more precise or compelling. The Conservative contention is that Mr Brown is to blame for the current economic malaise because he “did not fix the roof while the sun was shining”. I don't know how many people you saw on roofs this weekend, but the Prime Minister was hardly unique in his absence.

What I understand Mr Cameron to mean, though, is that, because when he was Chancellor Mr Brown built up borrowing to fund new spending in the earlier part of this decade, we cannot extend the public deficit today when that would be helpful to the country. This would be a fair accusation if the Tories had opposed the increase in resources to the NHS, or had insisted that higher spending should be funded by higher taxation, not borrowing. They did neither, and it is still their stance now that they will retain current ministerial spending plans until at least 2011.

A similar inconsistency can be found in the Conservative approach to the public services. They are no longer to be confronted with a radical market-orientated agenda. Instead there will be “bottom-up reform” in which schools and hospitals are transformed by the professionals who have, apparently, been itching to revolutionise working practices but have been held back by irrelevant central targets from Whitehall. To call this optimistic is too kind. Be it the public sector or the private sector, the old ways are invariably the comfortable option for most of us. New ideas have to be imposed or they will never be implemented. “Bottom-up reform” is as plausible as bottom-up rain.

Why does this matter? Because the Conservatives are favourites to win the next election. There are two views of how one secures a meaningful mandate to govern. One is by maximising the majority, the other is by maximising the manifesto. Could I suggest two witnesses in favour of the case for maximising the manifesto?

The first is Margaret Thatcher. There is a myth around that her 1979 manifesto was not especially robust. It is certainly an interesting document in retrospect. The section on Europe which condemned the “obstructive and malevolent attitude” of some in the Labour Cabinet towards Brussels and which calls for a common EU foreign policy is ironic. The core of it, however, is unambiguous. It stated “we shall cut income tax at all levels”. It noted that: “Any future government which sets out honestly to reduce inflation and taxation will have to make substantial economies, and there should be no doubt about our intention to do so.” It was scathing about the nationalised industries and there were more words devoted to reducing the power of the trade unions than any other subject. Although the Tory majority that year was not vast (43), it had immense authority behind it to introduce necessary reforms.

The second is Tony Blair. In the mid-1990s he, like Mr Cameron, kept it vague and adopted positions that had the widest appeal and offended virtually nobody. He too sought the votes of the professionals in health and education by promising to scrap Tory measures. And he bitterly regretted it.

If you could provide Mr Blair with a swift trip in the Tardis he would trade a smaller majority in the 1997 election for a more substantial programme, rooted in a truly new Labour approach to reform. The principal tragedy of his premiership, he realises, is that he was not a Blairite from the outset.

In the coming months the Conservative Party will, whether it appreciates it or not, be faced with a similar decision about its strategy. Is it to be “time for a change (but mostly of faces)” or “time for a change (and of direction)”?

If the first course is chosen, the Tories will win Crewe & Nantwich on May 22 and have a decent shout of holding it at a general election in 2010 hustings. Yet what, if anything, would such victories actually mean?

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