diff --git a/docs/topics/request-response.rst b/docs/topics/request-response.rst
index 1cb724227..98906992d 100644
--- a/docs/topics/request-response.rst
+++ b/docs/topics/request-response.rst
@@ -693,12 +693,9 @@ Response objects
     :param ip_address: The IP address of the server from which the Response originated.
     :type ip_address: :class:`ipaddress.IPv4Address` or :class:`ipaddress.IPv6Address`
 
-    :param protocol: A tuple containing information about the protocol that was used
-        to download the response. Taken from the ``version`` attribute of the
-        corresponding :class:`twisted.web.client.Response` object, it will tipically
-        consist of the protocol and version numbers, e.g. ``(b"HTTP", 1, 1)``
-        to represent "HTTP/1.1".
-    :type protocol: :class:`tuple`
+    :param protocol: The protocol that was used to download the response.
+        For instance: "HTTP/1.0", "HTTP/1.1"
+    :type protocol: :class:`str`
 
     .. versionadded:: 2.0.0
        The ``certificate`` parameter.
@@ -814,14 +811,11 @@ Response objects
 
         .. versionadded:: VERSION
 
-        A tuple containing information about the protocol that was used
-        to download the response. Taken from the ``version`` attribute of the
-        corresponding :class:`twisted.web.client.Response` object, it will tipically
-        consist of the protocol and version numbers, e.g. ``(b"HTTP", 1, 1)``
-        to represent "HTTP/1.1".
+        The protocol that was used to download the response.
+        For instance: "HTTP/1.0", "HTTP/1.1"
 
-        This attribute is currently only populated by the HTTP 1.1 download
-        handler, i.e. for ``http(s)`` responses. For other handlers,
+        This attribute is currently only populated by the HTTP download
+        handlers, i.e. for ``http(s)`` responses. For other handlers,
         :attr:`protocol` is always ``None``.
 
     .. method:: Response.copy()
diff --git a/scrapy/core/downloader/handlers/http11.py b/scrapy/core/downloader/handlers/http11.py
index 0f30b01f9..c7553eb87 100644
--- a/scrapy/core/downloader/handlers/http11.py
+++ b/scrapy/core/downloader/handlers/http11.py
@@ -434,6 +434,11 @@ class ScrapyAgent:
     def _cb_bodydone(self, result, request, url):
         headers = Headers(result["txresponse"].headers.getAllRawHeaders())
         respcls = responsetypes.from_args(headers=headers, url=url, body=result["body"])
+        try:
+            version = result["txresponse"].version
+            protocol = f"{to_unicode(version[0])}/{version[1]}.{version[2]}"
+        except (AttributeError, TypeError):
+            protocol = None
         response = respcls(
             url=url,
             status=int(result["txresponse"].code),
@@ -442,7 +447,7 @@ class ScrapyAgent:
             flags=result["flags"],
             certificate=result["certificate"],
             ip_address=result["ip_address"],
-            protocol=getattr(result["txresponse"], "version", None),
+            protocol=protocol,
         )
         if result.get("failure"):
             result["failure"].value.response = response
diff --git a/scrapy/core/downloader/webclient.py b/scrapy/core/downloader/webclient.py
index c13683393..9524cce2b 100644
--- a/scrapy/core/downloader/webclient.py
+++ b/scrapy/core/downloader/webclient.py
@@ -7,7 +7,7 @@ from twisted.internet.protocol import ClientFactory
 
 from scrapy.http import Headers
 from scrapy.utils.httpobj import urlparse_cached
-from scrapy.utils.python import to_bytes
+from scrapy.utils.python import to_bytes, to_unicode
 from scrapy.responsetypes import responsetypes
 
 
@@ -110,7 +110,7 @@ class ScrapyHTTPClientFactory(ClientFactory):
         status = int(self.status)
         headers = Headers(self.response_headers)
         respcls = responsetypes.from_args(headers=headers, url=self._url)
-        return respcls(url=self._url, status=status, headers=headers, body=body)
+        return respcls(url=self._url, status=status, headers=headers, body=body, protocol=to_unicode(self.version))
 
     def _set_connection_attributes(self, request):
         parsed = urlparse_cached(request)
diff --git a/tests/test_downloader_handlers.py b/tests/test_downloader_handlers.py
index eb6d40df7..a8763a7a5 100644
--- a/tests/test_downloader_handlers.py
+++ b/tests/test_downloader_handlers.py
@@ -360,6 +360,13 @@ class Http10TestCase(HttpTestCase):
     """HTTP 1.0 test case"""
     download_handler_cls = HTTP10DownloadHandler
 
+    def test_protocol(self):
+        request = Request(self.getURL("host"), method="GET")
+        d = self.download_request(request, Spider("foo"))
+        d.addCallback(lambda r: r.protocol)
+        d.addCallback(self.assertEqual, "HTTP/1.0")
+        return d
+
 
 class Https10TestCase(Http10TestCase):
     scheme = 'https'
@@ -493,7 +500,7 @@ class Http11TestCase(HttpTestCase):
         request = Request(self.getURL("host"), method="GET")
         d = self.download_request(request, Spider("foo"))
         d.addCallback(lambda r: r.protocol)
-        d.addCallback(self.assertEqual, (b"HTTP", 1, 1))
+        d.addCallback(self.assertEqual, "HTTP/1.1")
         return d