Gosport Tower

Has been described as a Certain Artillery Fort, and also as a Certain Chain Tower

There are no visible remains

NameGosport Tower
Alternative NamesFort Blockhouse; Chiderodd
Historic CountryHampshire and the Isle of Wight
Modern AuthorityHampshire
1974 AuthorityHampshire
Civil ParishGosport

One of the original defences of the principal entrance to Portsmouth Harbour, Blockhouse began as a boom tower erected in the reign of Edward VI to hold one end of a boom chain. It was subsequently improved and enlarged and became known by its present title some time in the eighteenth century (Hogg).

The Henrician tower was in a state of decay by 1585 and although proposals were made to replace it, little seems to have been done. As the Western end of the 'harbour chain', it appears to have been replaced by a fixed point or perhaps capstan to hold the chain until de Gomme redesigned the harbour defences. In 1667 he built an L-shaped battery there with 17 or 18 guns facing South-East and 2 South-West (Williams 1979). (PastScape)

he original Blockhouse was constructed between 1420-1422 at the north-eastern end of the spit in a natural position for defending the entrance to Portsmouth Harbour, opposite the still surviving Round Tower on the Portsmouth side. Both were connected by a chain which could be raised to close the harbour entrance. in 1542 Leland described The Blockhouse as a round stone tower with ordnance. Both the Blockhouse and Bulwark are shown on a portrait of 1545 as a round tower with supporting buttresses and battlements and a larger two-tiered circular fortification respectively, although the accuracy of this portrait is open to question. However, an armament list of c.1547 mentions the Bulwark but not the Blockhouse, possibly suggesting that the latter had been disarmed by this date. Indeed, the Blockhouse is not shown on a map of c.1588 the Bulwark was described as old and decayed and its remains were still visible as a mound in early-mid 17th century. (Hampshire AHBR)

Gatehouse Comments

Held east end of harbour chain, west end held by Round Tower, Portsmouth. A supplementary bulwark Lymden's Bulwark, lay to the south.

- Philip Davis

This site is a scheduled monument protected by law

Not Listed

Historic England (PastScape) Defra or Monument number(s)
County Historic Environment Record
OS Map Grid ReferenceSZ626992
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  • Salter, Mike, 2002, The Castles of Wessex (Malvern: Folly Publications) p. 50
  • Pettifer, A., 1995, English Castles, A guide by counties (Woodbridge: Boydell Press) p. 93 (slight)
  • King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol. 1 p. 195
  • Williams, G.H., 1979, The Western Defences of Portsmouth Harbour 1400-1800 (Portsmouth City Council)
  • Williams, G.H., 1974, Earlier Fortifications of Gosport (Gosport Historic Records and Museum Soc) p. 10-14
  • Hogg, I.V., 1974, Coast Defences of England and Wales, 1856-1956 (David & Charles) p. 139
  • Comey, A., 1966, Fortifications in Old Portsmouth p. 30
  • Page, Wm (ed), 1908, VCH Hampshire and the Isle of Wight Vol. 3 p. 187 online transcription


  • Chandler, John, 1993, John Leland's Itinerary: travels in Tudor England  (Sutton Publishing) p. 208, 209
  • Toulmin-Smith, Lucy (ed), 1907, The itinerary of John Leland in or about the years 1535-1543 (London: Bell and Sons) Vol. 1 p. 282 online copy

Primary Sources

  • Gairdner, J. and Brodie, R.H. (eds), 1896, Letters and Papers, Foreign and Domestic, Henry VIII Vol. 15 p. 131 no. 323 online copy
  • c. 1548, The Encampment of the English forces near Portsmouth, Together with a view of the English and French fleets at commencement of the action between them on the XIXth  July MDXLV (Cowdray picture) For a discussion of this picture see Dominic Fontana, The Cowdray engravings and the loss of the Mary Rose


  • Dave Hopkins, 2004, Extensive Urban Survey - Hampshire and the Isle of Wight (English Heritage) Download copy
  • C. Donnithorne, 1999, Fort Blockhouse