If we can get fusion to work, it is the answer, but nobody has yet managed to create a sustained plasma. Best they've managed is a very short plasma where energy out exceeded the energy in.Fusion is the answer if we had invested at the same level as fission we might be there.
Safer process much lower, radiation in spent fuel, the Tokamak is progressing slowly but with the Hinkley C budget we may have been there.
Up until now, the main technology to achieve fusion hasn't existed, and it's probably safe to say that the technology to achieve it continually and reliably still doesn't physically exist.
There's a big difference between spending £xx billion on a proven technology, and spending it on technology that might not be physically achievable.
People have been saying fusion will be viable within the next decade, for several decades now, yet it's still not happened. Although with recent developments, it is getting closer.