Question: is there such thing as a 100 pound note

Answer: Yes, Not since 1945 has there been bigger notes than £50 issued for general circulation by the Bank of England, although banks in Scotland and Northern Ireland still use £100 notes. However, the Bank of England does produce higher-value notes that are used to maintain parity with Scottish and Northern Irish notes. Banknotes issued by Scottish and Northern Irish banks have to be backed pound for pound by Bank of England notes (other than a small amount representing the currency in circulation in 1845), and special £1 million and £100 million notes are used for this purpose. Their design is based on the old Series A notes.