This would count as oversize baggage given the length is 100cm (max length standard baggage is 90cm) but it shouldn't cost any extra charge as less than your 32 KG allowance. Take note if it contains any batteries, you must follow the advice on BA website https://www.britishairways.com/en-gb...d-restrictions and note that you should ensure that it is well packed as suggested as it is unlikely to be covered under the liability for general luggage.