Giddy’s background was solidly Cornish, his maternal grandfather whose small estate he inherited being ‘the representative of several old Cornish houses’. The curacy of St. Erth was the ‘only preferment’ his father ‘ever enjoyed’, though he secured a competence by dabbling in mining ventures. Cyrus Redding, who knew Giddy as a boy, recalled that he was ‘whimsical, full of projects, of which he would demonstrate the feasibility by algebra’, but added ‘ingenious as he was, [he] never brought to pass anything of moment. He loved money, and fluxions, and in politics was one day a Royalist, and the next a Cromwellian— never fixed.’ He realized his great ambition of becoming an FRS at 24 and kept company with radical intellectuals like Thomas Beddoes. Dr Parr, the Whig panjandrum, dubbed him ‘the Cornish philosopher’.
In politics, Giddy first admired Pitt and canvassed for the minister’s friend Francis Gregor in the county election of 1790. He then went through a radical phase, during which he more than once attended debates at Westminster. He was weaned from this by Sir Francis Basset’s securing his nomination as sheriff in 1792: ‘it took me from companions who might have hurried me into excesses, notwithstanding my own moderate opinions’. In May 1796 he took down a copy of the French constitution of 1791 that had hung on his sitting room wall since then and concentrated on his scientific pursuits.
Giddy was returned by (Sir) Christopher Hawkins for Helston in May 1804 just after Pitt’s return to power. He had assisted Hawkins to secure the patronage of the borough, but was his guest. Charles Williams Wynn, meeting him on the London-Oxford coach, reported to Southey on 6 May 1805:
His conversation was the most entertaining and full of information, his appearance disgustingly mean. Since that time one who knows him intimately has told me that his coming into Parliament was equally extraordinary with everything else about him— inasmuch that with decided opposition principles and an independent fortune he had accepted Sir Christopher Hawkins’s offer of being brought in professedly to support the minister for the time being, whoever he may be, in order to foster Sir Christopher’s jobs and that he makes no secret of the wish he entertains in contradiction to every vote he gives.
This is borne out by a letter from Lord de Dunstanville (the former Sir Francis Basset) to Addington, the fallen minister, 16 Nov. 1804, in which he wrote, ‘Davies Giddy and his father are your sincere well-wishers; you know however that Mr Davies Giddy is so circumstanced that he cannot show it as he wishes’. In fact, two days after taking his seat, he was at first reported as having voted against Pitt’s additional force bill, 8 June 1804, with his patron; but the report was contradicted. Addington, who seems to have thought Giddy and his patron were on his side, had to make do with Giddy’s apologies until his reconciliation with Pitt gratified them both.
Giddy was listed ‘Pitt’ in September 1804 and July 1805, having voted like his patron against the censure of Melville, 8 Apr. 1805, but against his own judgment. Like other Cornish Members he had voted against the salt tax bill, 4 Mar.: it was the subject of his maiden speech, in the interest of the pilchard fisheries. He brought in a bill to promote them on 27 June. He remained a champion of Cornish interests throughout his parliamentary career. On 7 June 1805 he voted against compensation for the Duke of Atholl and on 19 July spoke to the same effect, arguing that if compensation was insisted on, it should be out of the public purse. He was a spokesman on corn bounties, 28 June, having published an anonymous pamphlet on the subject the year before. On 28 Mar. 1806 his patron, having found a bidder for Giddy’s seat on the change of ministry, asked him to surrender it in a manner as ‘unliberal as unexpected’. De Dunstanville offered to find him a seat elsewhere.
Giddy was returned by De Dunstanville for Bodmin at the general election of 1806. In one source he was listed in the minority on the Hampshire election petition, 13 Feb. 1807, but on 16 Feb. he applauded the Grenville ministry’s ‘new plan of finance’, which he claimed to have scrutinized. Like his patron and Sidmouth he turned against the ministry a month later. In the Parliament of 1807, when he might have come in for East Looe had he not preferred to remain Member for Bodmin, he began to speak regularly in the House, being an assiduous attender. Farington reported that Giddy was ‘devoted to the business of Parliament and is becoming so well informed in all that relates to it, that it is not improbable but that he may at some period be the Speaker’.
When Perceval came to power, a bid was made for Giddy’s services: the secretaryship to the Board of Control was offered him. He declined it, 28 Nov. 1809, on his patron’s advice. De Dunstanville wrote of him to Sidmouth that day: ‘with much talent, great information, and a perfectly honourable mind our friend’s two faults (his only faults I believe) are a good deal of vanity and a love of money’— whence ‘something of a hankering after office’. Giddy’s marriage to an heiress who brought him £100,000 and a fine marine view at Eastbourne had already changed his prospects. If, as Bragge Bathurst suggested, he would have lost his seat by accepting office against his patron’s wishes, he was at that very time prepared to negotiate with the Duke of Bedford for his borough interest at Camelford which, if not on his own behalf, might have secured him a broker’s reward of a seat.
Giddy was proposed by George Johnstone for the committee on commercial credit, 1 Mar. 1811, but no Member would second it. He supported the findings of the committee on bullion, 9 May 1811, having published a pamphlet A plain statement on the bullion question, which provoked two replies. A member of the select committee on the distress of the cotton workers, he was unsympathetic, advising them to go back to the land, 24 June 1811; on 5 May 1812 he denounced the Luddites. On 21 Jan. 1812 he ‘stated his conversion’ to relieving the crown of the droits of Admiralty.
Giddy appeared on the Treasury list of supporters after the election of 1812. On 3 Mar. 1813 he criticized Vansittart’s new plan of finance as detrimental to the sinking fund, though he would not go so far as to vote against it. A week later he started his parliamentary campaign for the revision of the laws of copyright. The death of his eldest son in May 1813 depressed him and he was less active than in the previous Parliament. His support for alteration of the Corn Laws, on which he was a select committeeman, caused his town house to be attacked by the mob in March 1815. After the failure of his own proposals in 1813, he repeatedly opposed other proposals for reform of the borough of Helston until 1816. As chairman of the committee on Irish currency, he recommended the union of the two treasuries, 19 June 1815. He was in the government majority against inquiry into the Regent’s expenditure, 31 May, but in the opposition majority against the grant to the Duke of Cumberland, 3 July 1815: it was this kind of conduct that earned him the epithet (bestowed on him by Thomas Wallace) ‘crotchetty’.
On 25 Oct. 1815 Sidmouth indicated that he would welcome Giddy’s replacing Hiley Addington as under-secretary to him at the Home Office, but nothing came of it then.