Halliday & Matthiessen (2014: 542):
Another, minor but significant, environment in which fact clauses occur is that of ‘existential’ clauses (an environment favoured by evidence):
There is evidence [[that the Russians were just as surprised as anyone else at the suddenness and violence of them]], but it is, of course, a situation ideal for exploitation.
If the serum of a D negative individual agglutinates the D positive but not the D negative control cells, there is a high probability [[that the serum contains anti-D]], but the specificity should be confirmed by testing against several more examples of D-positive and D-negative red cells.