In a parliamentary system, the government is, by definition, the party (or coalition) of parties which controls the lower house (in the UK, the House of Commons).
In particular, achieving parliamentary approval for supply -- i.e. the ability to spend money -- is a make or break issue for a government, akin to vote of confidence. If a government loses supply, it means that it no longer has control of the house, which typically triggers a general election.
As for the upper house: in the UK, the House of Lords has only attempted to block supply once in the last 300 years, when it attempted to reject the "People's Budget" of 1910/11. This ultimately led to the Lords having their power to block supply removed, and there hasn't been such a crisis again since.
So to summarise: a loss of supply is very unlikely (though not impossible) in the UK, because the government controls the Commons, and the Lords don't have the power to reject it.
See also: fact sheet on parliamentary financial procedure.