Do English subjects need a visa to visit Bulgaria or Romania?

Bulgaria and Romania are EU countries so you don't need a visa if you are a citizen of an EU country; you don't need a passport either if you have a national issued identity card (it's not the case for UK citizens). You can stay/work here indefinitely but if your stay exceeds 90 days in a 180 days period you need to register as a local resident.

On 1 January 2007 both Bulgaria and Romania became members of the EC, therefore UK citizens do not need visas or work permits in either country. Finding work might be harder than you think unless you have a good knowledge of the local language, few locals speak English.

Contact the embassies for advice. You probably don't need a work permit as these countries are part of the EU, but best to check first. You won't need a visa if you're planning to visit for a holiday but if you want to work or study, the entry requirements might be different.

They are now EU member states, you don't need a visa merely to visit and travel around. Good luck with finding casual work though.