It very much depends on what your contract states regarding working hours and your employers right to amend them. So check this first. If you need advice about your contract contact ACAS, their website is www.acas.org.uk
I am guessing your comment about the Working Time Directive relates to time off between shifts - you should have 11 hours off between the end of a shift and and the start of the next one. Again ACAS will give you advice on Working Time Directive.
Are there other shift workers who are affected. It may be that together you can approach your employer to negotiate a shift pattern that suits all needs. Other avenues you might pursue if you have dependants is to request an amendment under Flexible Working; this can however be declined due to business needs. Or to consider whether the new shift pattern discriminates against a particular group, say working parents. Unfortunately if your employer has built amendments to working hours into your contract, as shift worker, you might find they already have this covered - although it is usual to give 28 days notice (or I think it's one week for every year of employment) to amendments.
Check your contract, get advice, and feedback to your employer about how poor this approach is - issues like this are so avoidable if your employer had just consulted and communicated with you.