It depends on how hungry I might be - if I am I'll eat or drink whatever takes my fancy or is convenient or ready to hand, but often a mug of coffee with cream or just a drink of water is all i want, but I've never been a great breakfast eater.
While a bacon & egg, etc breakfast is possibly the UK norm, as already mentioned other countries break their fasts with different food: e.g. cold meat and/or cheeses, pastries, or cake - I ate yummy honey cake for breakfast years ago on holiday in Greece, and mouth puckering yoghurt from little bottles in Yugoslavia. But often just a coffee with cream ( or added butter &cocnut oil - that infamous Bulletproof Coffee) can actually keep you satisfied until lunch time - or possibly even longer. Low carb higher fat should keep you well satisfied, so it's not always necessary to start eating early in the day.
Robbity