Classic whataboutism, accusing your critic of exactly what you have been exposed as doing. This is a recurring pro-Kremlin disinformation narrative about the Salisbury poisoning. The claim about the UK allegedly staging the Skripals' poisoning is an unfounded conspiracy theory.
UK police and intelligence investigations have produced hard evidence which is sufficient to charge two Russian nationals for the attack on the Skripals. These two individuals have been established as officers of the Russian Military Intelligence, GRU. More British public documents/statements on the case here and here.
The EU Member States support the UK findings, and decided unanimously to introduce sanctions against the GRU officers responsible and their commanding officers.
More similar cases on this issue.