[kypro]

Markets don't care about politics, they care about risk and reward.

By fuelling growth in a period of high inflation with debt you basically add to the existing inflationary pressures and increase risk.

As an investor you want your investment to at least yield more than inflation so this is one reason why the market is demanding a higher interest rate (the market now excepts UK inflation could run hotter), but they're also worried about the risk of extra borrowing so are also demanding a higher risk premium because of the uncertainty of their investment.

Also, I'd argue this isn't really a "right-wing" fiscal policy. Cutting taxes might be "right-wing" but borrowing to do so certainly isn't something that's universally popular with those on the right. Most on the right probably want tax cuts to be funded by spending cuts.