Avoid war; don't trust flatterers, courtiers and ministers; and most importantly 'retrieve the glory of the Throne'.

Just some of the advice given by Frederick, Prince of Wales (shown left) to his son, the future George III, (below), in a previously unseen letter of 1749.

The letter reveals sound advice that includes:

'The sooner you have an opportunity to lower the interest, for God's sake, do it… if you can be without war, let not your ambition draw you into it… Flatterers, Courtiers or Ministers, are easy to be got, but a true Friend is difficult to be found... Let your steadiness retrieve the glory of the throne.'

Written 'out of love' and sent with 'the tenderest paternal affection', it urges the future monarch to reduce the national debt, ease the tax burden and to behave as 'an Englishman born and bred'.

The eldest son of George II Frederick was first in line to the throne, however, he died prematurely, just two years after writing this letter, and so never took the crown. With eerie prescience he wrote to his son, 'I shall have no regret never to have wore the Crown, if you do but fill it worthily'.

Frederick credits his grandfather, George I, for his ideas, rather than his father. The roots of his antipathy towards his parents can be traced back to the time when, at just seven years of age, he was left behind in Hanover. Separated from Frederick for 13 years, George II clearly favoured his second son, William, Duke of Cumberland.

Once in London, Frederick presented himself as a fashionable man about town, entertaining freely and informally.

Frederick's mother, Queen Caroline, despised her son's relaxed manner: ‘popularity always makes me sick’, she is reported to have said, ‘but Fretz’s popularity makes me vomit'.

In 1737 Frederick fell out spectacularly with his parents after arranging for his first daughter to be born in St James's Palace, rather than at Hampton Court as his father had decreed. Frederick and his family were publicly forced to leave St James's Palace to cheering crowds.

Father and son were uneasily reconciled in 1742, although the relationship never fully healed. However, when Frederick died, George II joined in the mourning for his son and declared six months of official mourning at court.