Subsidence- should I be worried?

[geebaxter]

We moved into our Victorian (1875) home nearly 2 years ago. Have only recently noticed these cracks - should we be worried?

The patio has been removed below window presumably as this is where the previous owners planned to open up to an extension (which we haven't done) and I'm assuming the builder/architect did this. Photos are inside / outside of the same window.

 

[RonnyRaygun]

More likely to be due to the concentrated stresses under the brick panel below the window. Quite common to get minor cracking there. Not indicative of subsidence which is usually long diagonal cracks that go through opposite corners of windows (if there are any) and gradually widen from bottom to top, or widening vertical cracks in the case of extensions butted up to existing buildings.
Very minor and not of any concern.

BRE Digest 251 describes the cracks as follows:

0: Hairline cracks of less than about 0.1 mm which are classed as negligible. No action required.

1: Fine cracks which can be treated easily using normal decoration. Damage generally restricted to internal wall finishes; cracks rarely visible in external brickwork. Typical crack widths up to 1 mm.

2: Cracks easily filled. Recurrent cracks can be masked by suitable linings. Cracks not necessarily visible externally; some external repointing may be required to ensure weather-tightness. Doors and windows may stick slightly and require easing and adjusting. Typical crack widths up to 5 mm.

Yours are somewhere between 1 and two I would think - i.e. less than 1mm but visible externally.