Haplogroup H

mtDNA (maternal line)

The most common maternal lineage in Europe today; expanded across the continent from the Neolithic onward. [isogg][aadr]

The British record

In the ancient British record

Frequency of H among ancient samples from Britain & Ireland, by period — from our aggregation of the CC0 Allen Ancient DNA Resource. See the full chart.

Bronze Age 28%
Early Medieval 40%
Iron Age 41%
Medieval+ 63%
Mesolithic 9%
Neolithic 19%
Roman 41%

Fuller account: H on Wikipedia.

Remember: a haplogroup is a deep, broad lineage shared by many people — not an ethnicity, a nationality or a clan. See what DNA can and can’t tell you.

Sources

[isogg] International Society of Genetic Genealogy (ISOGG), Y-DNA Haplogroup Tree. Reference — cite for haplogroup nomenclature only (not frequencies) · link
[aadr] Allen Ancient DNA Resource (AADR) v66, Mallick & Reich (Harvard), doi:10.7910/DVN/FFIDCW. CC0 1.0 (public domain dedication) · link