First while r (the interest rate) declined, g (nominal growth) remained much lower in Spain than in the UK.
The latter was due to the deflationary forces in the Eurozone – themselves a result of excessive austerity and the absence of currency depreciation (which was made possible in the UK thanks to the expansionary monetary policies of the Bank of England). As a result, r – g continued to be positive in Spain, thereby keeping Spain on an explosive debt path.
Second, as Spain was kept on an explosive debt path, it was forced to apply stronger austerity measures.
These in fact did not help to solve the Spanish fiscal crisis as it fed back into a low g, keeping Spain on the same explosive debt path. We know from history that it is generally not a good idea to fight excessive debt levels by organising deflation. This lesson from history was forgotten in Europe.