govuk-frontend/dist/govuk/components/checkboxes/template-small.html

GOV.UK Frontend contains the code you need to start building a user interface for government platforms and services.

<div class="govuk-form-group">
  <fieldset class="govuk-fieldset">
  <legend class="govuk-fieldset__legend">
    Filter by
  </legend>
  <div class="govuk-checkboxes govuk-checkboxes--small" data-module="govuk-checkboxes">
    <div class="govuk-checkboxes__item">
      <input class="govuk-checkboxes__input" id="nationality" name="nationality" type="checkbox" value="a">
      <label class="govuk-label govuk-checkboxes__label" for="nationality">
        a thing
      </label>
    </div>
    <div class="govuk-checkboxes__item">
      <input class="govuk-checkboxes__input" id="nationality-2" name="nationality" type="checkbox" value="b">
      <label class="govuk-label govuk-checkboxes__label" for="nationality-2">
        another thing
      </label>
    </div>
    <div class="govuk-checkboxes__item">
      <input class="govuk-checkboxes__input" id="nationality-3" name="nationality" type="checkbox" value="c">
      <label class="govuk-label govuk-checkboxes__label" for="nationality-3">
        this thing
      </label>
    </div>
  </div>
</fieldset>
</div>